feat: Add support for using Sitecore.Logging and log4net together

[chynesNR]

A customer attempted to use Sitecore.Logging and log4net in the same application. Sitecore.Logging uses an old fork of log4net that has different properties, and the instrumentation was not built to handle both at once. The wrapper would throw errors and eventually be disabled. Now they will work side by side.

This also adds the ability to run integration tests on multiple loggers at once, in case we run into other similar logging conflicts in the future.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.50%. Comparing base (227003a) to head (f60d898).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2537      +/-   ##
==========================================
+ Coverage   80.47%   80.50%   +0.02%     
==========================================
  Files         459      459              
  Lines       28775    28873      +98     
  Branches     3153     3167      +14     
==========================================
+ Hits        23158    23244      +86     
- Misses       4837     4843       +6     
- Partials      780      786       +6     

Flag	Coverage Δ
Agent	81.49% <ø> (+0.02%)	⬆️
Profiler	71.71% <ø> (ø)

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see 6 files with indirect coverage changes