Remove redundant code

[stephen-riggs]

Removes the Monitor and Processor classes which are never used.

Removes the demo api and all demo references

One strange aspect is the _flush_{grid_square/foil_hole}_records functions which seem to be in an incomplete atlas_registered workflow

[codecov]

Codecov Report

❌ Patch coverage is 63.33333% with 11 lines in your changes missing coverage. Please review.
✅ Project coverage is 46.00%. Comparing base (58b66ba) to head (058da2b).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #723      +/-   ##
==========================================
+ Coverage   43.98%   46.00%   +2.02%     
==========================================
  Files          93       91       -2     
  Lines       10189     9624     -565     
  Branches     1320     1256      -64     
==========================================
- Hits         4482     4428      -54     
+ Misses       5486     4977     -509     
+ Partials      221      219       -2     

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[tieneupin]

Looks good! I've tested the CLEM and tomo workflow, and it looks like it's running OK. Thanks for getting this done!