Fix starting order for `RollbackSynchronizer`

[TheYellowArchitect]

Solves #260 and #268 by fixing input initialization.

Also gets rid of the await 1 frame hack for 2 seperate classes (BrawlerController.gd/player.gd) in order to await for input authority to be set before process_authority, so this awaiting a frame logic is moved to RollbackSynchronizer since in most games, input authority is set in _ready or something similar.

May also solve the reported problem of the first 2 ticks, having NPCs spinning. Haven't seen it in a project of mine, but it may solve it because this PR addresses the first _earliest_input being set properly