Make it easy to generate roles for the dr-cluster and hub flavor of the operator

[raghavendra-talur]

Currently, we run the make manifests target to generate the crds, roles, webhooks for the code we have in our repo.

This generates the config/rbac/role.yaml file for the roles. Then the developer has to copy the updated/generated lines over to the right file config/hub/rbac/role.yaml or config/dr-cluster/rbac/role.yaml depending on where the +kubebuilder:rbac: lines were updated.

This is

1. manual
2. error-prone
3. not documented

We should make this process easier.

More details:

1. output one shows where we have the +kubebuilder:rbac marker lines in our code.
2. output two shows the current splits between dr-cluster and hub roles.

$ grep -nri "+kubebuilder:rbac:" ./* | grep -v "Binary file" | cut -d":" -f1 | sort | uniq
./internal/controller/drcluster_controller.go
./internal/controller/drclusterconfig_controller.go
./internal/controller/drplacementcontrol_controller.go
./internal/controller/drpolicy_controller.go
./internal/controller/kubeobjects/velero/requests.go
./internal/controller/protectedvolumereplicationgrouplist_controller.go
./internal/controller/replicationgroupdestination_controller.go
./internal/controller/replicationgroupsource_controller.go
./internal/controller/volumereplicationgroup_controller.go


$ wc -l config/rbac/role.yaml config/dr-cluster/rbac/role.yaml config/hub/rbac/role.yaml
     434 config/rbac/role.yaml
     275 config/dr-cluster/rbac/role.yaml
     220 config/hub/rbac/role.yaml
     929 total

[nirs]

Let's start by documenting the process of adding new rbac rules. I'm sure that if you ask current developers how to do this most will fail to describe the right process.