Include ancillary variables and cell_measures during intersect

[ESadek-MO]

🚀 Pull Request

Closes #5413.

To do:

• Add rough functionality
• Refactor functions into one consolidated
• Add tests

[codecov]

Codecov Report

Attention: Patch coverage is 67.85714% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 89.74%. Comparing base (7c313ff) to head (522c247).
Report is 26 commits behind head on main.

Files	Patch %	Lines
lib/iris/cube.py	67.85%	8 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5804      +/-   ##
==========================================
- Coverage   89.76%   89.74%   -0.02%     
==========================================
  Files          93       93              
  Lines       22982    23024      +42     
  Branches     5006     5021      +15     
==========================================
+ Hits        20630    20664      +34     
- Misses       1622     1628       +6     
- Partials      730      732       +2     

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[ESadek-MO]

Two notes on last commit:

• I decided against consolidating create_coord into create_metadata as it would require so many if checks and the like it would've been harder to read. That said, I'm happy to be vetoed on this.
• This PR threw up some flake8 errors from previous changes; cube was being used as a variable despite being imported as well. All these instances have been changed to c instead