Add CODEOWNERS file pointing to review team

[callumforrester]

Fixes #901

To be merged after changes to repository settings...

Instructions to reviewer on how to test:

1. Open CODEOWNERS file in Github viewer and confirm that Github lints it
2. Verify that the referenced team exists
3. Verify that codeowner review is required in the dodal repository settings (requires admin access)

Checks for reviewer

• Would the PR title make sense to a scientist on a set of release notes
• If a new device has been added does it follow the standards
• If changing the API for a pre-existing device, ensure that any beamlines using this device have updated their Bluesky plans accordingly
• Have the connection tests for the relevant beamline(s) been run via dodal connect ${BEAMLINE}

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.70%. Comparing base (ad6cc0d) to head (02a8772).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #902   +/-   ##
=======================================
  Coverage   95.70%   95.70%           
=======================================
  Files         132      132           
  Lines        5334     5334           
=======================================
  Hits         5105     5105           
  Misses        229      229           

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[DiamondJoseph]

Github insists that the file is valid so I can't disagree

[DominicOram]

I think we need to be ready for the "soft" side of this before merging. So I would like to see:

• Some documentation on how codeowners are decided
• Some documentation giving the policy that "All code must be approved by code owners" and reasoning
• This change communicated with all of DAQ, probably by slack and a group meeting

I'm obviously happy to help on this if needed

[DiamondJoseph]

Justifying my slightly glib comment above that I thought this was still testing in Callum's repo