manage appprojects in *-app

[hairmare]

Is your feature request related to a problem? Please describe.
Currently, we manage a AppProject for each application we deploy. Often most of the info we need to create the AppProject is already in the app:

• destination namespace
• source helm chart

Other info is often consistent over various deployments but not currently tracked in *apps charts:

• resource allow list (for cluster-wide stuff)

Describe the solution you'd like
We might benefit from (optionally) creating AppProjects directly in *-apps charts.

I'd l like to enable them individually for apps. Values to do so might look like so (example from first app in infra-apps):

argocd:
  # Enable the Argo CD app deployment
  name: argocd
  # current definition of "project" is a string for injection into the app and might need redefining
  project:
    create: true
    # more appproject settings go here
  # ... snip

There are other possibilities to model the data, see below for a projects as top-level key approach.

Describe alternatives you've considered
Well, there is the status quo that i'm not happy with.

We could also create additional *-appproject charts but i'm wary of the additional maintenance burden for such a solution.

An alternative way to implement values would be like so:

argocd:
  # Enable the Argo CD app deployment
  name: argocd
  # keep current definition of project for app
  project: "argo-cd"
  # ... snip

# new top-level key containing all the apps.
projects:
  argocd:
    create: true
    # name here would need to match `argocd.project` (or have some magick in the template to only grab it from there)
    name: "argo-cd"
    # more appproject settings go here

Affected chart

• all *-app charts

Additional context
The argoconfigs has been ready for this for a while now, we just never got to implementing it.

https://github.com/adfinis-sygroup/helm-charts/blob/b66006a29f2c9df27fd642bc94f9035a7ca5bb47/charts/argoconfig/templates/_appProject.yaml#L1-L17

[hairmare]

Current solution is to use misc-apps:

---
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: misc-apps
  namespace: infra-argocd
spec:
  destination:
    namespace: infra-argocd
    server: https://kubernetes.default.svc
  project: infra-argocd
  syncPolicy:
    automated: {}
    syncOptions:
      - CreateNamespace=true
  source:
    chart: misc-apps
    repoURL: https://charts.adfinis.com
    targetRevision: "*"
    helm:
      values: |
        fullnameOverride: app
        argocdApps:
          enabled: true
          project: infra-argocd
          syncPolicy:
            automated: {}
            syncOptions:
              - CreateNamespace=true
          destination:
            server: https://kubernetes.default.svc
            namespace: infra-argocd
          values:
            projects: []

I still think this issue should be something to consider tho.