Make runner Role/RoleBinding reconciliation idempotent

This MR updates the runner app Role/RoleBinding reconciliation functions to be idempotent. If they already exist in a Runner namespace they are now updated if diverged. If a Runner CR is created within the Operator namespace the gitlab-runner-app-rolebinding which serves as template will be updated too with the correct namespace in the subjects/namespace ref.

Additionally, in the future when a new Operator version will ship an updated gitlab-runner-app-role all existing gitlab-runner-app-role in all namespaces with an active Runner CR will be updated too.

Fixes #61 (closed)

How to test

1. Install the Operator with the catalog-source from this MR in a custom namespace.
2. Since the catalog source from the operator registry will be a certified Operator bundle, find the gitlab-runner-app-rolebinding in the Operator namespace
3. and re-add gitlab-runner-system as subjects/namespace ref to it (undo what the certification removed).
4. Create a Runner CR in the Operator namespace and the subjects/namespace ref should be updated to the correct Operator namespace.

kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: gitlab-runner-app-rolebinding
  namespace: gitlab-runner-operator
  uid: 38ee6fc3-ae47-4ad7-91fc-687d019f3d86
  resourceVersion: '122166818'
  creationTimestamp: '2022-04-15T09:32:38Z'
  managedFields:
    - manager: catalog
      operation: Update
      apiVersion: rbac.authorization.k8s.io/v1
      time: '2022-04-15T09:32:38Z'
      fieldsType: FieldsV1
      fieldsV1:
        'f:roleRef': {}
    - manager: manager
      operation: Update
      apiVersion: rbac.authorization.k8s.io/v1
      time: '2022-04-15T09:38:47Z'
      fieldsType: FieldsV1
      fieldsV1:
        'f:subjects': {}
subjects:
  - kind: ServiceAccount
    name: gitlab-runner-sa
    namespace: gitlab-runner-operator
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: gitlab-runner-app-role