feat: avian!

Merge branch 'core/rewrite-it-all-again-lmao' into 'master'

unified

See merge request starkingdoms.tk/starkingdoms.tk!5

feat: basic part functionality

chore(part): part fix #1

feat: part & attachment beginnings

feat: mod spawning

feat: bloom!

chore(lint): lint/format

player input

gravity

planets