Fix Xposed args code generation

[iscle]

This PR fixes issues when generating Kotlin Xposed code. The function types were not generated correctly for primitive types and for non common java types.

For example:

• int was "int.class", which in Kotlin should have been "Int::class.javaPrimitiveType".
• Unknown types were also like "an.unknown.type.class", which of course does not exist in the Xposed module. It is now just ""an.unknown.type"".

This change also affects generated Java code in that now all, except some specific, classes will be in string form instead of ending in ".class".

The implementation was also converted to Kotlin to make it a bit cleaner and nicer to follow :) I hope you don't mind!

[iscle]

It would be nice to write some unit tests for this, but I don't know how to do that yet :(
Contributions are welcome!

[skylot]

@iscle look good.
A possible minor improvement is to use variables in strings (string interpolation) instead of String.format. And same for logs (with replace logger to kotlin wrapper).

It would be nice to write some unit tests for this

Well, for good test we need actually execute xposed, but this is need emulator and so is too much hassle.
Another way is trying to compile outputs to verify code correctness, this is doable, but I am not sure if this will be helpful.
Also, now xposed and forks repos are in archived state and not active, so I don't think spending time on test will worth it.