[ENHANCEMENT] Rework how hot reloading behaves

[nykwono]

Fixes issues:
Funkin#7915

Right now hot-reloading behaves really finicky as it simply just loads the state's constructor.
Because of this, there are a couple bugs like:

• Hot-reloading in PlayState doesn't update the song script (This is because after hot-reloading, PlayState updates its params but it isn't accounted for now.)
• You aren't really able to playtest charts anymore in the Chart Editor.

This PR reworks how hot-reloading is handled, attempting to give states more control of its behavior by:

• HotReloadState is now initialized given a HotReloadStateParams object containing:
  • onComplete callback for after hot-reloading is finished.
  • targetState for the state to go to after finishing (Defaults to the state's constructor).

If targetState is null, it'll first assume that onComplete is the one handling state switching, else it fallbacks to going back to the TitleState.

• States now have functions onPreHotReload(), onPostHotReload(), & getHotReloadParams
  • onPreHotReload() is called right before hot-reloading begins, allowing states to save any necessary information needed.
  • onPostHotReload() is called right after hot-reloading is finished and create() is called when the state is initialized.
  • getHotReloadParams() is a function that states can override incase they have a specific way they want to hot-reload (For ex. PlayState doesn't use targetState to hot-reload and instead utilizes onComplete() to switch back.)

With this rework, the above issues are fixed and you're now able to go into a chart and playtest it with it saving.

Courtesy of @ComedyLost for helping with fixing this issue!

[realvirtu]

ENHANCMENET

[nykwono]

ENHANCMENET

it was 3am when i made this PR I call this harassment 🥀 🥀 🥀 🥀 🥀 🥀

[EliteMasterEric]

I'll review this more thoroughly later but it seems well thought out