feat: Add ruff and fix issues

[marksweb]

This switches flake8 and isort for ruff along with a thorough set of rules and appropirate excludes for the existing codebase.

[codecov]

Codecov Report

Merging #923 (44a4b34) into main (6090c9f) will increase coverage by 0.65%.
Report is 4 commits behind head on main.
The diff coverage is 82.08%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #923      +/-   ##
==========================================
+ Coverage   80.21%   80.87%   +0.65%     
==========================================
  Files          95       95              
  Lines        2856     2855       -1     
  Branches      274      269       -5     
==========================================
+ Hits         2291     2309      +18     
+ Misses        507      494      -13     
+ Partials       58       52       -6     

Files	Coverage Δ
applications/decorators.py	100.00% <100.00%> (ø)
applications/services.py	66.66% <100.00%> (ø)
coach/models.py	78.37% <100.00%> (ø)
core/context_processors.py	100.00% <ø> (ø)
core/default_eventpage_content.py	83.33% <100.00%> (ø)
core/deploy_event.py	100.00% <100.00%> (+5.26%)	⬆️
core/management_utils.py	97.29% <ø> (ø)
core/models/event.py	95.40% <100.00%> (+1.14%)	⬆️
core/quotes.py	0.00% <ø> (ø)
core/views.py	97.53% <100.00%> (+2.35%)	⬆️
... and 17 more

... and 1 file with indirect coverage changes

---

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[amakarudze]

So there are many coverage issues here @marksweb. Are you handling them or can I help with them so I can unblock my own PRs blocked by flake 8 issues?

[marksweb]

So there are many coverage issues here @marksweb. Are you handling them or can I help with them so I can unblock my own PRs blocked by flake 8 issues?

I'll take a look over it

[amakarudze]

LGTM! Thanks @marksweb.