Improving UTF-8 Support

[tankerkiller125]

The following kinds of bugs regarding UTF-8 are known and require the following kinds of changes/steps:

Problems:

• [x] UTF-8 Usernames are unsupported (https://github.com/flarum/core/issues/1949 and https://github.com/flarum/core/issues/1990) (fixed via https://github.com/flarum/nicknames)
  • [x] User slugs are currently hard coded to be the username (fixed with Slug Drivers)
• [x] Discussion slugs can not be UTF-8 and transliteration does not work for some languages/cultures (CJK) (https://github.com/flarum/core/issues/194) (fixed with slug drivers)
• [ ] UTF-8 search is awful (https://github.com/flarum/core/issues/2003)
  • [x] In some languages a single character is a single word or even sentences (min search length is now a constant that extensions can override)
• [ ] Scrubber date info is hard coded format, will need to localize that.