Refactor internal functions and add unit tests

[ehennestad]

• Deleted SchemaInspector class - Replaced by openminds.internal.meta.Type
• Renamed openminds.internal.abstract.LinkedCategory to openminds.internal.abstract.MixedTypeSet
• Moved some introspection methods from openminds.abstract.Schema to openminds.internal.meta.Type
• Fixed some bugs in MetaTypeRegistry class that was recently added
• Added unit tests for enumeration classes, openminds.internal.meta namespace and downloading a Github repo

[github-actions]

Test Results (R2021b)

516 tests  +6   516 ✅ +6   1m 23s ⏱️ +23s
 13 suites +3     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit fa0770e. ± Comparison against base commit 04f07c8.

♻️ This comment has been updated with latest results.

[github-actions]

Test Results (R2024b)

516 tests  +6   516 ✅ +6   1m 21s ⏱️ +24s
 13 suites +3     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit fa0770e. ± Comparison against base commit 04f07c8.

♻️ This comment has been updated with latest results.

[codecov]

Codecov Report

Attention: Patch coverage is 75.94937% with 19 lines in your changes missing coverage. Please review.

Project coverage is 73.35%. Comparing base (04f07c8) to head (fa0770e).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
code/internal/+openminds/+internal/+meta/Type.m	62.50%	15 Missing ⚠️
...minds/+internal/+utility/+git/downloadRepository.m	70.00%	3 Missing ⚠️
...nternal/+meta/@MetaTypeRegistry/MetaTypeRegistry.m	96.15%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #59      +/-   ##
==========================================
+ Coverage   65.30%   73.35%   +8.04%     
==========================================
  Files         323      320       -3     
  Lines        2678     2582      -96     
==========================================
+ Hits         1749     1894     +145     
+ Misses        929      688     -241     

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