[Refactor] Rewrite core

[vars1ty]

Such as using structures more and having variables in them, try and reduce the amount of variables created via lazy_static, etc.

[vars1ty]

Title updated to reflect on the issue better, will be done when I got time for it.
Will also happen in parallel with #38, one example of a much-needed rewrite is Config.
Old "structure":

New:

List:

• Rewrite Config base
• Sync Config changes across the project
• Look into rewriting how the Cava implementation works
• Refactor other core parts, such as ui

[vars1ty]

Commit c38c84f removed is_feature_active, which will be needed again later.