GitLab

- '/documentation': home page with all links
- '/documentation/handbook': html version of the gm handbook
- '/documentation/gachamapping': json document with the gacha mappings

* Autogenerate keys and data files

* Update gacha html files

Accidentally pushed with old html files

* Keys no longer copied. No more manually retrieving listing files. Recursive directory creation

Removed unused code from old GC as well.

* Moved somethings and better errors

* Fixed resources from loading twice

* Data files fallback

* 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

* Frontend is not very beautiful yet
* Didn't include too much `some anime game` data in the page to avoid being DMCA'd