docs: add kontinuous comments

.kontinuous/values.yaml

@@ -1,21 +1,25 @@
+# define docker registry options
 global:
   registry: harbor.fabrique.social.gouv.fr
   imageProject: fabrique
   imageRepository: template
 
+# main app container
 app:
+  # wait for build-app before deployment
   ~needs: [build-app]
   imagePackage: app
   containerPort: 8080
 
 jobs:
   runs:
+    # define a kubernetes job to build the docker image
     build-app:
       use: build
       with:
         imagePackage: app
         registrySecretRefName: harbor
-        skipExisting: true
         buildOptions: --single-snapshot --ignore-path=/product_uuid --compressed-caching=false # optim for local builds
+        # pass a custom docker build arg
         buildArgs:
           GITHUB_SHA: "{{ $.Values.global.sha }}"