Deprecate KRandomSequence in favour of QRandomGenerator

All the getters can be done directly or indirectly with QRandomGenerator generate() or bounded().

i.e. KRandomSequence::getBool can be done with QRandomGenerator::bounded(2)

For KRandomSequence::randomize you can use KRandom::shuffle

We don't have any replacement for KRandomSequence::modulate but there doesn't seem to be anyone using it