feat: support watching specific namespaces

[maxime1907]

Checklist

• Update changelog in CHANGELOG.md.

Proposal

Make it possible to watch only for a specific set of namespaces for Silence CR changes.
Doesn't change the actual behavior of the operator as it remains cluster wide by default.
Breaking change in the CRD to make its scope Namespaced.

[QuentinBisson]

What's your use case to restrict it to namespace?

[maxime1907]

What's your use case to restrict it to namespace?

We have RBAC enforced on our clusters that strictly splits every client in its own namespace managed by a specific team.
So with the current implementation of silence-operator, we cannot let these specific teams manage silences since they only have rights to list resources in their authorized namespaces.

[maxime1907]

Any update @QuentinBisson ?

[maxime1907]

Any update @hervenicol ?

[hervenicol]

Sorry @maxime1907, end of year was a bit rough.
@QuentinBisson should be the one giving approval. In January hopefully, as he still is rather busy.

[maxime1907]

Sorry @maxime1907, end of year was a bit rough. @QuentinBisson should be the one giving approval. In January hopefully, as he still is rather busy.

Okay no problem, thank you for answering!

[maxime1907]

Any update/Are you still busy @QuentinBisson ?

[sebastiangaiser]

Any updates on this?