[Enhancement Proposal] Replay system

[sqirradotdev]

Taking an example from osu!, adding a replay system (even as an internal thing) would benefit a lot for this game. Some points:

• Deterministic botplay
  Botplay input can be calculated ahead of time instead of during the gameplay. This would make botplay deterministic, as it is just the same as playing any other replay, except that the inputs are perfect, eliminating any potential misses and imperfections.
• Evidence of score achievement
  Replay data usually records input data. This replay data then can be uploaded/shared to anyone. This may come off as competitive, which I understand that this engine may not.

I will try to spin up a draft PR at some point for the initial implementation. Thanks!

[nebulazorua]

to be fair the botplay issue can be fixed by just forcing a certain judgement (i.e in Troll we force it to Epic or Sick)

[sqirradotdev]

to be fair the botplay issue can be fixed by just forcing a certain judgement (i.e in Troll we force it to Epic or Sick)

That's a weird but working fix. I just wanted an excuse to implement a sick and cool feature as a practice :D

[crowplexus]

feel free to do it if you wanna :D