Theme updates

[Spuds]

This addresses items remaining form Theme css suggestions #2284

This also adds a couple of more variants gold and blue, to ensure the core css structure was easy to change via variant files

Of course going through all this you find other template / php bugs so there were addressed here as well.

Improved slidedown function with a callback option

Added a sticky menu feature for themes to use should they want (gold does this)

General cleanup along the way

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 43.50%. Comparing base (1ed00a8) to head (c3e98ef).
Report is 1 commits behind head on development.

Additional details and impacted files

@@                Coverage Diff                @@
##             development    #3791      +/-   ##
=================================================
- Coverage          43.50%   43.50%   -0.01%     
- Complexity         13905    13910       +5     
=================================================
  Files                347      348       +1     
  Lines              74759    74773      +14     
=================================================
+ Hits               32527    32529       +2     
- Misses             42232    42244      +12     

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