[V3] Multi-group controller import alias

[Adirio]

In v2, when multi-group is enabled, controllers are imported as [GROUP]controller:

kubebuilder/testdata/project-v2-multigroup/main.go

Lines 36 to 39 in 5dc6055

	crewcontroller "sigs.k8s.io/kubebuilder/testdata/project-v2-multigroup/controllers/crew"
	foopolicycontroller "sigs.k8s.io/kubebuilder/testdata/project-v2-multigroup/controllers/foo.policy"
	seacreaturescontroller "sigs.k8s.io/kubebuilder/testdata/project-v2-multigroup/controllers/sea-creatures"
	shipcontroller "sigs.k8s.io/kubebuilder/testdata/project-v2-multigroup/controllers/ship"

However, any of those alias can contain multiple controllers:

1. shipcontroller:

   1. kubebuilder/testdata/project-v2-multigroup/main.go

      Line 97 in 5dc6055

      if err = (&shipcontroller.FrigateReconciler{

   2. kubebuilder/testdata/project-v2-multigroup/main.go

      Line 109 in 5dc6055

      if err = (&shipcontroller.DestroyerReconciler{

   3. kubebuilder/testdata/project-v2-multigroup/main.go

      Line 117 in 5dc6055

      if err = (&shipcontroller.CruiserReconciler{

2. shipcontroller:

   1. kubebuilder/testdata/project-v2-multigroup/main.go

      Line 125 in 5dc6055

      if err = (&seacreaturescontroller.KrakenReconciler{

   2. kubebuilder/testdata/project-v2-multigroup/main.go

      Line 133 in 5dc6055

      if err = (&seacreaturescontroller.LeviathanReconciler{

In v3, the import alias should be renamed to the plural version: [GROUP]controllers

Code to modify:

kubebuilder/pkg/scaffold/internal/templates/v2/main.go

Lines 92 to 96 in 5dc6055

	// TODO(v3): `&%scontrollers` should be used instead of `&%scontroller` as there may be multiple
	// controller for different Kinds in the same group. However, this is a backwards incompatible
	// change, and thus should be done for next project version.
	multiGroupControllerImportCodeFragment = `%scontroller "%s/controllers/%s"
	`

/kind feature

[camilamacedo86]

/assign @camilamacedo86