feat: doc mgrs can edit/remind action holders

[jennifer-richards]

Expands permissions for editing a document's action holders or sending a reminder email. Instead of AD / secretariat, allows document managers for the document's group to take these actions.

Fixes #3391, which asked for chairs rather than document managers. Given the discussion, I think this is a logical thing to do, but I can scale back to chairs only if that makes more sense.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.84%. Comparing base (c7f6bde) to head (6b4bf1c).
Report is 81 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #7971      +/-   ##
==========================================
+ Coverage   88.78%   88.84%   +0.05%     
==========================================
  Files         296      304       +8     
  Lines       41320    41544     +224     
==========================================
+ Hits        36687    36910     +223     
- Misses       4633     4634       +1     

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