Mapex 184 stop capability group pages from overwriting capability pages

[allisonrobbins]

• moved capability groups into folder so there's no pages getting overwritten

and also fixed a few small misc things:

• add previous_link variable to banner and version badges to remove errors with those links
• fix subtechnique ATT&CK website links
• updated formatting for a few css things- fixed cursor on version badges, just made things more consistent across pages

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (62b6a36) 23.77% compared to head (c655995) 23.71%.

Files	Patch %	Lines
src/mappings_explorer/site_builder.py	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #80      +/-   ##
==========================================
- Coverage   23.77%   23.71%   -0.07%     
==========================================
  Files          11       11              
  Lines        1413     1417       +4     
==========================================
  Hits          336      336              
- Misses       1077     1081       +4     

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