Simplify the JctFileManagerImpl class into a separate repository

[ascopes]

This splits up the file manager system into smaller components to reduce complexity of each
class.

There is now a separate repository mediator class, and module discovery is performed in a utility class in the utils package instead, enabling reuse and easier ability to swap out the existing implementation with new logic in the future, should it be needed. This also makes it easier to stub module detection in tests by using MockedStatic in Mockito

[codecov-commenter]

Codecov Report

Merging #287 (23cba55) into main (e92e588) will decrease coverage by 0.26%.
The diff coverage is 53.80%.

❗ Current head 23cba55 differs from pull request most recent head 31b35c6. Consider uploading reports for the commit 31b35c6 to get more accurate results

@@            Coverage Diff             @@
##             main     #287      +/-   ##
==========================================
- Coverage   71.02%   70.76%   -0.26%     
==========================================
  Files          87       89       +2     
  Lines        2671     2740      +69     
  Branches      233      237       +4     
==========================================
+ Hits         1897     1939      +42     
- Misses        702      722      +20     
- Partials       72       79       +7     

Impacted Files	Coverage Δ
...opes/jct/filemanagers/impl/JctFileManagerImpl.java	43.20% <41.53%> (-6.05%)	⬇️
.../containers/impl/ContainerGroupRepositoryImpl.java	57.57% <57.57%> (ø)
.../io/github/ascopes/jct/utils/ModuleDiscoverer.java	72.72% <72.72%> (ø)
...ManagerAnnotationProcessorClassPathConfigurer.java	100.00% <100.00%> (ø)
...containers/impl/AbstractPackageContainerGroup.java	48.27% <0.00%> (+1.14%)	⬆️
.../jct/containers/impl/ModuleContainerGroupImpl.java	21.21% <0.00%> (+1.51%)	⬆️

[github-actions]

Test Results

  1 291 files  ±  0    1 291 suites  ±0   0s ⏱️ ±0s
16 832 tests  - 24  16 820 ✔️  - 24  12 💤 ±0  0 ❌ ±0 
17 096 runs   - 24  17 084 ✔️  - 24  12 💤 ±0  0 ❌ ±0 

Results for commit 31b35c6. ± Comparison against base commit e92e588.