Making it a library instead of including the source from multiple places
has several advantages. We get proper dependency and include path
propagation. We can specify the krdb dependencies once instead of
repeating them for each kcm. This allows for a better separation between
the KCM's actual dependencies and krdb's dependencies.
We currently need the lookandfeel and style kcm in plasma-workspace, but
appearantly they depend on the krdb so best solution is to move all kcms
together
They are taken from plasma-desktop at the commit :
8447c08e878ccbde9c5516ba8a912993ea199cb9