Migrate the plugins system to be like the Tachiyomi one #449
Description
Instead of having static json files which are limited in what they can do, difficult to manage and implement new features, Tachiyomi uses an extension system where people can create an apk and install it to use it to search and read mangas.
A system like this has several advantages and only one downside, that apks can be harmful for your phone.
While Tachiyomi is now closed, several forks are up and anyway we need to reimplement their system, we don't care about it.