[FEAT] Type in answer cards with auto-check

Is addressed in #459. I'm also working on a fork of this plugin with first class editing support.

Thanks @AB1908 for contributing to this plugin, this has been very helpful to my course-work. I couldn't find in the readme/settings how to create a type-in-answer card, let me know the syntax

@mayukhc @AB1908 do you think that type-in-answer cards should be defined separately by unique separator or just with global on/off setting? I think both of these could be useful. Global on/off setting would make every basic cards defined by :: to type-in-answer cards.

If we think this broader, then card appearance and card content should be separate entities. Why to implement new and new separators if we could just assign one custom style to cards and then the user could make changes to the custom style like adding type-in box etc.

Other point of view: users that want more customisation could just use Anki. In a sense type-in-answer cards already replicate a lot of Anki. We don't want to reproduce all the hard work that has been put to Anki because that doesn't make any sense.

@maggaou Separating card style from content is cleaner than adding new separator for every content-style combo. Also if the setting is review-level instead of global, we can type-in/just mentally recall depending on situation.

Regarding the feature overlap with Anki, I think most users of this plugin want not just spaced repetition, but spaced rep plus PKM/task management system. So some overlap with Anki is unavoidable as Anki doesn't have PKM/task management system. For pure spaced repetition, Anki would definitely be better.