IDP-1416 Add support for workleap certificate store

[starcraft66]

Description of changes

Added support to mount Workleap's certificate store over the container's internal certificate store. The store comes from a well-known Key Vault who's information must be filled in via helm values.

Breaking changes

Removed the volumes section that was briefly introduced (without being documented) into the chart because it is redundant and less flexible than extraVolumes. No one is using it AFAIK.

Additional checks

Tested using server-side dry-run on a dev cluster:

PS C:\Users\tristan.g-hane\src\gsoft-helm-charts> helm template --set certificateStore.enabled=true test ./charts/aspnetcore --debug | kubectl apply --dry-run=server -f -
install.go:218: [debug] Original chart version: ""
install.go:235: [debug] CHART PATH: C:\Users\tristan.g-hane\src\gsoft-helm-charts\charts\aspnetcore

poddisruptionbudget.policy/test-pdb created (server dry run)
service/test-service created (server dry run)
deployment.apps/test-deployment created (server dry run)
ingress.networking.k8s.io/test-ingress created (server dry run)
secretproviderclass.secrets-store.csi.x-k8s.io/internal-dns-keyvault created (server dry run)

• Updated the documentation of the project to reflect the changes
• Added new tests that cover the code changes