mnit apps: add metatada files suitable for FDroid

So people can improve and update them.
See https://f-droid.org/manual/fdroid.html#Metadata for details.

Signed-off-by: Jean Privat <jean@pryen.org>
Merge: mnit apps: add metatada files suitable for FDroid

So people can improve and update them.
See https://f-droid.org/manual/fdroid.html#Metadata for details.

Pull-Request: #556
Reviewed-by: Alexis Laferrière <alexis.laf@xymus.net>
Reviewed-by: Alexandre Terrasa <alexandre@moz-code.org>