feat: WIP Rebindable hotkeys

[grifinas]

This is just me telegraphing upcoming PR and trying to get early(ish) feedback

Motivation:

• As a user I'd like to be able to rebind the hotkeys to something i find more intuitive
• As a user with accessibility needs, I'd like to rebind the hotkeys to keys that better suit my abilities.
• As a developer, I want to add new bindings without risking conflicts with existing user workflows

Description:
This PR adds the ability for the user to rebind existing hotkeys. It refactors all existing hotkeys behind actions. Allows new developers to, at a glance see what actions are available and to compose/modify them easier.

Notes:

• UI's not done. Need buttons to rebind, delete, add, reset keybind. Also will change how HTML is constructed
• Keybinding structs are a bit of a mess, will eventually expose a more cohesive thing
• Added lazyLoad JS function to allow devs to add scripts without changing HTML files. Will probably not end up using it in final PR, since it complicates the dependency dynamics
• Not tested on Internet Explorer, i don't have Windows.
  • Also there's no contribution guidelines for browser support. https://github.com/9001/copyparty?tab=readme-ov-file#browser-support Implies that ie6 is a target, but not all features are supported by it
  • On the other hand, https://github.com/9001/copyparty/blob/hovudstraum/CONTRIBUTING.md makes no mention of targeted versions. Would be nice to clear that up.
  • Personally, I would like to not support browsers that https://developer.mozilla.org does not even list in compatibility charts.
• Assuming Older browser support is optional I would at least like to use templates instead of generating string HTML
• Need to go through all other UI elements where hotkeys are hinted and make them resolve the hotkeys that the user is currently using
• Need to make ? hotkey also render the new hotkeys, not the OG
• Eventually, though maybe not with this iteration, i'd be nice if adding a hotkey was just the modification of one struct with maybe a function definition for the implementation. Devs could refer the the action when they want to execute it making the code vastly more readable. e.g. execute(HOTKEY_ACTIONS.PLAY_PAUSE)

This PR complies with the DCO; https://developercertificate.org/