Include cluster name in Topic and Subscription name for Broker

[grac3gao-zz]

Problem
Once PR #950 lands, controller can get clusterName from resource's annotation (if it is running in GKE).

It would be useful to include cluster name in Topic and Subscription name for Broker, for users can find the resources associated with a cluster more easily.

Persona:
Which persona is this feature for?

Exit Criteria
Include cluster name in Topic and Subscription name for Broker

Time Estimate (optional):
How many developer-days do you think this may take to resolve?

Additional context (optional)
Add any other context about the feature request here.

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.

[grac3gao-zz]

/remove-lifecycle stale

[grantr]

Closing this for now. It's no longer clear this is a good idea and cluster name is kind of hard to get.