Remove legacy MantaMatcher files

[JasonWildMe]

With the new, React-based manual annotation tool in place and supporting bounding box rotation, we can remove legacy MantaMatcher tools that were kept around only to support manual annotation of mantas, which requires bounding box rotation.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 4.27%. Comparing base (b269d09) to head (7f0b9b3). Report is 29 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##              main   #1122      +/-   ##
==========================================
+ Coverage     4.22%   4.27%   +0.05%     
+ Complexity     257     255       -2     
==========================================
  Files          590     585       -5     
  Lines        64596   63636     -960     
  Branches     11482   11398      -84     
==========================================
- Hits          2727    2721       -6     
+ Misses       61715   60755     -960     
- Partials       154     160       +6     

Flag	Coverage Δ
backend	4.27% <ø> (+0.05%)	:arrow_up:
frontend	4.27% <ø> (+0.05%)	:arrow_up:

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