Revert "second attempt, let's clean up"

This reverts commit 8c21abb08b7516ef6ea128cebac3da6be83bc39d.
Revert "reintroduce the old ColorPickerDialog"

This reverts commit 7c3a4f452329ec29033d4b1916fa8dfda6be4a1c.
rewrite color handling @ LockscreenInterface