Fix user and user_path in FSNode for subpath deployments

[vwbusguy]

Fixes #296 .

Changes proposed in this pull request:

• Regex instantiated on import for performance
• Regex to fetch accurate user path regardless of subpath
• Regex to fetch accurate user regardless of subpath

Tested against three Nextcloud instances, with or without /nextcloud and index.php in the path.

[vwbusguy]

The tests don't lie. My comment had the correct regex but my original PR commit didn't. Fix incoming.

[vwbusguy]

I think I've found a fix for the test regressions but it appears to be awaiting approval to run the tests against the most recent commit.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.81%. Comparing base (aef1ed2) to head (986fa1f).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #297   +/-   ##
=======================================
  Coverage   94.81%   94.81%           
=======================================
  Files          46       46           
  Lines        5341     5346    +5     
=======================================
+ Hits         5064     5069    +5     
  Misses        277      277           

Files with missing lines	Coverage Δ
nc_py_api/files/__init__.py	99.69% <100.00%> (+<0.01%)	⬆️

[bigcat88]

Looks ok to me.
Thank you very much for the pull request.