Add fallback stripping and C6 stripping
Converting banner definitions from pity vars to lerp arrays
Properly implement rates and pool smoothing
Also move reusable functions to Utils
* fix achievement proto
TakeAchievementRewardReq tells client the achievements achieved or not and it's progress.
* add import
* Add all AvatarExpedition protos
Expedition system has almost done but still has some bug so it will be uploaded later
* Add all expedition rewards
* Auto generate mapping files with command `java -jar grasscutter.jar -gachamap`
* Static file provider
* For gacha record webpage
* All static files should be stored at `GRASSCUTTER_RESOURCE/gcstatic/`
* Can benefit other subsystem in future when webpages involved