Add watch-namespaces to spicedb-operator cmd

[sumedha-redd]

#291 (comment)

Introduce --watch-namespaces argument to the spicedb-operator cmd, which accepts a comma-separated list of namespaces to watch. Update the controller to set up informers for each namespace. If the argument is not set, the operator continues to work at a cluster-wide level using NamespaceAll.

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[sumedha-redd]

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[sumedha-redd]

recheck

[ecordell]

Couple of small comments. I'd also like to see a test for this (showing that the operator can't see objects in namespaces it hasn't been given access to) - let me know if that's something you think you can tackle; I can follow up with it later if needed.

[sumedha-redd]

@ecordell Thanks for the feedback!
Regarding adding a test for this — I looked into the e2e suite and tried updating the operator options here to set Options.WatchNamespaces with a random namespace name. This caused the tests to fail with errors while fetching resources, which seems like the expected behavior here.
I'm not sure how to go about updating the cmd Options for the operator only for a specific test case though. Could you help with that?

[ecordell]

LGTM

Thanks @sumedha-redd - let's go ahead and merge this and I'll follow up with a PR adding a test