[Suggestion] Extra event: TwitchSpawn start/stop

[StefanJanssen95]

My streamer friend wants to have a possibility to have a donation where gamerule "keepInventory" will be toggled on for the remainder of the stream, but wants to have it reset back to false in the next stream.

Having the TwitchSpawn start and stop events would allow that to happen automatically without having to do it manually.