Convert keyboard selection feature to separate keyboards

[andrewtavis]

Terms

• [x] I have searched open and closed feature requests
• [x] I agree to follow Scribe-Android's Code of Conduct

Description

As a part of #12, the way keyboards are selected needs to be changed so it matches Scribe-iOS. Not every user will need each keyboard, but some will need more than one, and eventually keyboards will be downloadable packs. Scribe-Android should thus include different keyboards, not a single one that can be changed to different languages. This will also allow for the settings icon to be removed from keyboards, which will save room for auto suggest and complete functionality as well as annotation features.