Update handling of namespace watching:

[jacobweinstock]

Description

CLI flag to watch one or all namespaces.

Why is this needed

Fixes: #

How Has This Been Tested?

How are existing users impacted? What migration steps/scripts do we need?

Checklist:

I have:

• [ ] updated the documentation and/or roadmap (if required)
• [ ] added unit or e2e tests
• [ ] provided instructions on how to upgrade

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 21 lines in your changes missing coverage. Please review.

Project coverage is 30.75%. Comparing base (8c7a9c8) to head (348742d). Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/tink-controller/main.go	0.00%	21 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1011 +/- ## ========================================== - Coverage 30.86% 30.75% -0.11% ========================================== Files 75 75 Lines 3923 3937 +14 ========================================== Hits 1211 1211 - Misses 2617 2631 +14 Partials 95 95 ```

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