GitLab

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>