Android app whitelist/blacklist feature

[Jason A. Donenfeld]

Hey Eric,

On cursory glance, this looks really good; well done. It might be
desirable to have an easy toolbar icon for deselecting all apps. Great
that you managed to use RecyclerView. We'd like to use that on the
main tunnel list fragment, but haven't done so yet [1] (if you feel so
inclined and want to give it a spin.)

I'll let Samuel do a proper of the code.

Regards,
Jason

[1] https://docs.google.com/document/d/15i0Z750eL_OlUyrypUFLF7Hoi5eoF-dTFWj-Rs4RXGI/edit