Add feature flag for the admin map panel

[sagnew]

The Django admin was having loading issues associated with the map panel, so I put the scripts that load the iframe behind a feature flag. This flag's state can be managed in the admin panel.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.04%. Comparing base (973d88b) to head (31e4916).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1125   +/-   ##
=======================================
  Coverage   95.04%   95.04%           
=======================================
  Files         100      100           
  Lines        4605     4605           
=======================================
  Hits         4377     4377           
  Misses        228      228           

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[WillNilges]

Tested locally and seems to work. Thanks!