Remove creation of cluster role in service account reconcile of connect cluster

[ranatrk]

Update on #3086

What changed?
Use exisiting cluster role instead of creating a new one for the service account

Why was this change made?
To reduce number of resources created when an existing resource can be used

How was this change implemented?

• Remove creation of cluster role
• Use exisiting cluster role cluster-admin when creating the cluster role binding

How did you validate the change?

• Explain how a reviewer can verify the change themselves
  Given a hub and spoke cluster, runnning the following command and checking for the created resources in the spoke cluster and secret with kubeconfig in the hub cluster

./gitops connect cluster --namespace default --service-account test-service-account  --cluster-role-binding test-service-account  --connect-context <SPOKE_CONTEXT_NAME> <SPOKE_CLUSTER_NAME>

note: won't work directly if the spoke cluster is a local kind cluster because the IP will be localhost

• Unit tests -- what is covered, what cannot be covered; are
  there tests that fail without the change?

Release notes

Documentation Changes

Other follow ups

[bigkevmcd]

I suspect at some point we'll end up introducing a way to customise the ClusterRoleBinding but we don't need it just now.

Thanks for this1