Kotlin Symbol Processing(ksp) Support

[bespaltovyj]

The new Kotlin documentation says that kapt is in maintenance mode and new features are not planned.
And recommend using ksp(it should work faster).

Will you support ksp?
If you don't mind, then I can start adding ksp support.

This issue has already been raised, but there the main problem was in using kapt with JDK 16.

[snicoll]

@bespaltovyj we'd rather reopen the original issue (that you've commented as well).