Summary:
We switch between controller (singular) and controllers (plural) throughout our codebase.
I've always found this to be an annoying and doesn't strike me as logical. I've heard one explanation that says we differentiate between # of controlller files within this package. That's not true upon inspection. I don't think there is any good reason to differentiate these and I propose we just rename everything to controllers instead.

Test Plan: Ran all tests and builds and they pass.

Reviewers: vihang, michelle, nserrino, zasgar

Reviewed By: vihang
Signed-off-by: Phillip Kuznetsov <pkuznetsov@pixielabs.ai>

Differential Revision: https://phab.corp.pixielabs.ai/D10252

GitOrigin-RevId: f2dc5724f9d31cd7b3edee0fd3a9ee7582cb6877