Original commits:
* Clean-up
* Introduce a new application arguments parser & handler
* Clean-up and deprecate `Tools#getLanguageOption`
* Fix `-debug` and `-debugall` parameters
* found this while debugging, ...why
* Remove deprecated parameters
* Invoke startup argument parser before handbook generation
* Move command map instantiation to `Grasscutter `(prevent making 3 instances on startup)
* Ensure \n at EOF
Co-authored-by: AnimeGitB <AnimeGitB@bigblueball.in>
- '/documentation': home page with all links
- '/documentation/handbook': html version of the gm handbook
- '/documentation/gachamapping': json document with the gacha mappings
