Reorganise and improve the monitoring docs

[stefanprodan]

This PR reorganises and improves the monitoring documentation.

Preview: https://deploy-preview-1628--fluxcd.netlify.app/flux/monitoring/

Completion status

• Monitoring
  • Alerts
  • Metrics
  • Custom metrics
  • Logs
  • Events
• ⚠️ remove the temporary website build fix commit

[darkowlzz]

I had to make a few changes for the website build to work locally. Just highlighting that the new controller releases have some changes to where the docs exist. I think the changes in #1577 should address this issue.

Temporarily, I made the following local changes to be able to build and see the preview:

diff --git a/hack/import-flux2-assets.sh b/hack/import-flux2-assets.sh
index e937c9a..21c4c0e 100755
--- a/hack/import-flux2-assets.sh
+++ b/hack/import-flux2-assets.sh
@@ -137,13 +137,13 @@ gen_crd_doc() {
   # kustomize-controller CRDs
   KUSTOMIZE_VER="$(controller_version kustomize-controller)"
   gen_crd_doc "https://raw.githubusercontent.com/fluxcd/kustomize-controller/$KUSTOMIZE_VER/docs/api/v1/kustomize.md" "$COMPONENTS_DIR/kustomize/api/v1.md" "HUGETABLE"
-  gen_crd_doc "https://raw.githubusercontent.com/fluxcd/kustomize-controller/$KUSTOMIZE_VER/docs/spec/v1/kustomization.md" "$COMPONENTS_DIR/kustomize/kustomization.md"
+  gen_crd_doc "https://raw.githubusercontent.com/fluxcd/kustomize-controller/$KUSTOMIZE_VER/docs/spec/v1/kustomizations.md" "$COMPONENTS_DIR/kustomize/kustomization.md"
 }
 
 {
   # helm-controller CRDs
   HELM_VER="$(controller_version helm-controller)"
-  gen_crd_doc "https://raw.githubusercontent.com/fluxcd/helm-controller/$HELM_VER/docs/api/helmrelease.md" "$COMPONENTS_DIR/helm/api.md" "HUGETABLE"
+  gen_crd_doc "https://raw.githubusercontent.com/fluxcd/helm-controller/$HELM_VER/docs/api/v2beta1/helm.md" "$COMPONENTS_DIR/helm/api.md" "HUGETABLE"
   gen_crd_doc "https://raw.githubusercontent.com/fluxcd/helm-controller/$HELM_VER/docs/spec/v2beta1/helmreleases.md" "$COMPONENTS_DIR/helm/helmreleases.md"
 }