Support running as a separate Pod

[faisal-memon]

Would be nice to be able to run controller manager in its own Pod. This request came in as spiffe/helm-charts-hardened#341 with the SPIRE helm charts. The linked ticket has some reasoning for the request.

[azdagron]

We started with UDS to punt on the authentication problem. If it is moved to a different pod, we'd need to figure out how to authenticate the controller with SPIRE and authorize it as an admin.

[kfox1111]

I could see how that would be extremely difficult to solve, without some kind of hackish auth solution. :/