feat: rely on Nx Parallel env var (#2561)

## Proposed change

feat: rely on Nx Parallel env var
docs: add developers explanation

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CONTRIBUTING.md

@@ -65,7 +65,9 @@ To ease the process, we are providing a set of:
 - [Linters configuration](./packages/@o3r/eslint-config/README.md)
 - [Component generator](./packages/@o3r/core/README.md#generators) (and more)
 
-### Accelerate your build thanks to Nx Cloud
+### Accelerate your build
+
+#### Thanks to Nx Cloud
 
 [Nx Cloud](https://nx.dev/nx-cloud) offers a way to accelerate the build of your project locally thanks to [Remote Cache](https://nx.dev/ci/features/remote-cache).
 
@@ -81,6 +83,18 @@ When building (`yarn build`) the project on the `main` branch (or another `relea
 > Only Otter Team members can write Remote Cache on Nx Cloud, logged-in users will be able to use Remote Cache in readonly mode.
 > The Local Cache is available for all users (logged or not to Nx Cloud).
 
+#### Increase the number of parallel process
+
+By default, the number of tasks that can run in parallel is 3 (see [Nx Documentation](https://nx.dev/recipes/running-tasks/run-tasks-in-parallel)).
+This number can be increased in the developer machine thanks to the [NX_PARALLEL](https://nx.dev/reference/environment-variables) environment variable by using the following command:
+
+```bash
+yarn print:nx-parallel >> .env
+```
+
+> [!NOTE]
+> The command will set this number to the maximum possible value for your machine, it can be adapted manually after generation
+
 ### DevTools to create new Otter monorepo elements
 
 To help developers create new items in the Otter monorepo, several scripts have been provided at root level to accelerate development:

package.json

@@ -8,31 +8,32 @@
     "ng": "yarn nx",
     "amaterasu": "node packages/@ama-terasu/cli/dist/src/cli/ama.js",
     "get:cpus-number": "node -e 'process.stdout.write(`${process.env.NX_PARALLEL || Math.max(require(\"os\").cpus().length - 1, 2)}`);'",
+    "print:nx-parallel": "node -e \"process.stdout.write(`NX_PARALLEL=$(yarn get:cpus-number)`)\"",
     "get:current-dir": "node -e 'process.stdout.write(process.cwd());'",
     "create:scope": "yarn create-monorepo-scope",
-    "build": "yarn nx run-many --target=build --parallel $(yarn get:cpus-number)",
-    "build:affected": "yarn nx affected --target=build --parallel $(yarn get:cpus-number) --output-style stream",
-    "build:tools": "yarn nx run-many --target=build --projects=eslint-plugin,workspace --parallel $(yarn get:cpus-number)",
-    "build:lint": "yarn nx run-many --target=build --projects=eslint-plugin --parallel $(yarn get:cpus-number)",
-    "build:swagger-gen": "yarn nx run-many --target=build-swagger --parallel $(yarn get:cpus-number)",
+    "build": "yarn nx run-many --target=build",
+    "build:affected": "yarn nx affected --target=build --output-style stream",
+    "build:tools": "yarn nx run-many --target=build --projects=eslint-plugin,workspace",
+    "build:lint": "yarn nx run-many --target=build --projects=eslint-plugin",
+    "build:swagger-gen": "yarn nx run-many --target=build-swagger",
     "prepare:publish": "yarn prepare-publish \"$(yarn workspaces:list)\" --append dist",
-    "publish": "yarn run prepare:publish && yarn nx run-many --target=publish --exclude=tag:private --parallel $(yarn get:cpus-number) --nx-bail",
-    "publish:extensions": "yarn nx run-many --target=publish-extension --parallel $(yarn get:cpus-number)",
-    "publish:extensions:affected": "yarn nx affected --target=publish-extension --parallel $(yarn get:cpus-number)",
-    "package-github-actions:affected": "yarn nx affected --target=package-github-action --parallel $(yarn get:cpus-number)",
-    "lint": "yarn nx run-many --target=lint --parallel $(yarn get:cpus-number)",
-    "lint:affected": "yarn nx affected --target=lint --parallel $(yarn get:cpus-number)",
-    "test": "yarn nx run-many --target=test --parallel $(yarn get:cpus-number) --cacheDirectory=$(yarn get:current-dir)/.cache/jest",
-    "test:affected": "yarn nx affected --target=test --parallel $(yarn get:cpus-number) --cacheDirectory=$(yarn get:current-dir)/.cache/jest",
-    "test-e2e": "yarn nx run-many --target=test-e2e --parallel $(yarn get:cpus-number)",
-    "test-int": "yarn nx run-many --target=test-int --parallel $(yarn get:cpus-number)",
+    "publish": "yarn run prepare:publish && yarn nx run-many --target=publish --exclude=tag:private --nx-bail",
+    "publish:extensions": "yarn nx run-many --target=publish-extension",
+    "publish:extensions:affected": "yarn nx affected --target=publish-extension",
+    "package-github-actions:affected": "yarn nx affected --target=package-github-action",
+    "lint": "yarn nx run-many --target=lint",
+    "lint:affected": "yarn nx affected --target=lint",
+    "test": "yarn nx run-many --target=test --cacheDirectory=$(yarn get:current-dir)/.cache/jest",
+    "test:affected": "yarn nx affected --target=test --cacheDirectory=$(yarn get:current-dir)/.cache/jest",
+    "test-e2e": "yarn nx run-many --target=test-e2e",
+    "test-int": "yarn nx run-many --target=test-int",
     "postinstall": "husky && yarn build:lint && yarn harmonize:version && yarn update-yarn-sdks",
     "update-yarn-sdks": "node -e \"'pnp' !== '$(yarn config get nodeLinker)' || process.exit(1)\" || yarn dlx @yarnpkg/sdks",
     "build:storybook": "yarn doc:generate:json && yarn ng run storybook:extract-style && build-storybook",
     "clear": "rimraf -g './{packages,tools,apps}/{@*/,}{amaterasu/,}*/{dist,build,dist-*}/'",
     "set:version": "yarn o3r-set-version --placeholder 0.0.0-placeholder --include '{apps,packages}/**/dist/{package,manifest}.json'",
     "harmonize:version": "eslint '**/package.json*' '.yarnrc.yml' --quiet --fix",
-    "doc:packages": "yarn nx run-many --target=documentation --parallel $(yarn get:cpus-number)",
+    "doc:packages": "yarn nx run-many --target=documentation",
     "doc:root": "yarn prepare-doc-root-menu-template && yarn update-doc-summary ./docs && yarn compodoc",
     "doc:generate": "rimraf ./generated-doc && yarn doc:root && yarn doc:packages && yarn doc-links --docs ./docs --generated-doc ./generated-doc",
     "doc:generate:json": "yarn update-doc-summary ./docs && yarn compodoc -e json -d .",
@@ -44,7 +45,7 @@
     "verdaccio:clean": "rimraf -g \".verdaccio/storage/@{o3r,ama-sdk,ama-terasu}\"",
     "verdaccio:login": "yarn cpy --cwd=./.verdaccio/conf .npmrc . --rename=.npmrc-logged && npx --yes npm-cli-login -u verdaccio -p verdaccio -e [email protected] -r http://127.0.0.1:4873 --config-path \".verdaccio/conf/.npmrc-logged\"",
     "verdaccio:prepare-publish": "yarn verdaccio:clean && yarn set:version 999.0.$(node -e 'process.stdout.write(String(Date.now()))') --include \"!**/!(dist)/package.json\" --include !package.json && yarn verdaccio:login && replace-in-files --regex=\"private(.*)true\" --replacement=private\\$1false '**/dist/package.json' && yarn run prepare:publish",
-    "verdaccio:publish": "yarn run verdaccio:prepare-publish && yarn nx run-many --target=publish --parallel $(yarn get:cpus-number) --nx-bail --userconfig \".verdaccio/conf/.npmrc-logged\" --tag=latest --@o3r:registry=http://127.0.0.1:4873 --@ama-sdk:registry=http://127.0.0.1:4873 --@ama-terasu:registry=http://127.0.0.1:4873 --@o3r-training:registry=http://127.0.0.1:4873",
+    "verdaccio:publish": "yarn run verdaccio:prepare-publish && yarn nx run-many --target=publish --nx-bail --userconfig \".verdaccio/conf/.npmrc-logged\" --tag=latest --@o3r:registry=http://127.0.0.1:4873 --@ama-sdk:registry=http://127.0.0.1:4873 --@ama-terasu:registry=http://127.0.0.1:4873 --@o3r-training:registry=http://127.0.0.1:4873",
     "verdaccio:stop": "docker container stop $(docker ps -a -q --filter=\"name=verdaccio\")",
     "verdaccio:all": "yarn verdaccio:stop && yarn verdaccio:start && yarn verdaccio:publish",
     "watch:vscode-extension": "yarn nx run vscode-extension:compile:watch",