Migrate to AndroidX

[flxholle]

No description provided.

[geecko86]

Hey there!

First of all, thank you! I'm guessing the reason you took the time to commit all these changes is because you enjoy using the app.
Sorry for the very delayed response. Work, a dislocated shoulder and my vacation got in the way.

A couple of things:

1. I've been very bad at maintaining this GitHub repo for the bast couple of years. QuickLyric has already been migrated to AndroidX (I encourage you to email me, next time!), which is why I will close your other PR (edit: I see you've made a lot more changes! I'll check it out).

2. The Romanizer app has not been migrated to AndroidX, which I why I will happily merge it.
   However, you shouldn't have committed your local.properties file. Could you please change that? Thanks!

3. I've had mixed experience publishing on F-Droid, I'm not sure I'm interested in working with them anymore.