(feat) Add PatchesFrom

[gianlucam76]

Profiles can now references ConfigMap/Secret instances containing
StrategicMerge or JSON Patch.

The namespace/name of the referenced ConfigMap/Secret can be expressed
as template.

Here is an example of a ClusterProfile Spec using PatchesFrom:

    patchesFrom:
    - kind: ConfigMap
      name: '{{ .Cluster.metadata.name}}-patches'
      namespace: '{{ .Cluster.metadata.namespace}}'
      optional: true
    - kind: ConfigMap
      name: '{{ .Cluster.metadata.name}}-jsonpatch'
      namespace: '{{ .Cluster.metadata.namespace}}'
      optional: true

and here are the ConfigMap one with StrategicMerge and one with JSON Patch

apiVersion: v1
data:
  deployment-labels: |-
    patch: |
      apiVersion: apps/v1
      kind: Deployment
      metadata:
        name: not-important
        labels:
          fv-5z5y6jvl78: fv-tawxs7qu93
    target:
      kind: Deployment
  fv-kwoqx4usiv: |-
    patch: |
      apiVersion: apps/v1
      kind: Deployment
      metadata:
        name: not-important
      spec:
        template:
          spec:
            tolerations:
            - key: fv-kwoqx4usiv
              operator: Equal
              value: example-value
              effect: NoSchedule
    target:
      kind: Deployment
  service-labels: |-
    patch: |
      apiVersion: v1
      kind: Service
      metadata:
        name: not-important
        labels:
          fv-5z5y6jvl78: fv-tawxs7qu93
    target:
      kind: Service
kind: ConfigMap
metadata:
  name: clusterapi-workload-patches
  namespace: default

apiVersion: v1
data:
  fv-kukz6aqz2x: |-
    patch: |-
      - op: add
        path: /metadata/annotations/fv-wfkjbenge9
        value: fv-mrxtndu2kx
    target:
      kind: Deployment
kind: ConfigMap
metadata:
  name: clusterapi-workload-jsonpatch
  namespace: default