refactor: split CI shell scripts into separate files for reusability/… #195

Job	Run time
prepare	2m 28s
Build (BossSloth/SteamHunter-plugin)	36s
Build (AdamRaichu/auto-accept-custom-launch-args)	35s
Build (ricewind012/aerothemesteam)	31s
Build (BossSloth/AugmentedSteam-Extension-Plugin)	58s
Build (shdwmtr/dwmx)	23s
Build (alowave/millennium-faceit-stats)	25s
Build (ricewind012/steam-browser-history)	43s
Build (BossSloth/Steam-SteamDB-extension)	41s
	7m 20s

Provide feedback