fix: use external searching

[ReenigneArcher]

Description

Doxygen search is... terrible.

This PR adds the ability to use an external search, with custom javascript.

Todo:

• create javascript class and initialization function, so we don't need to overwrite the original search.js file generated by Doxygen
• improve javascript table creation
• improve formatting
• add custom css to highlight the search terms
• change default rtd project slug to doxyconfig instead of sunshinestream

Screenshot

Issues Fixed or Closed

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components