This is in line with the frameworks naming policy, camelcasing. Up until
now, libplasma was the only library being KF5::plasma, that is now
KF5::Plasma.
- Installs PlasmaConfig, FindPlasma, PlasmaMacros, etc.
- find_package Plasma works
- version set to 2.0.0, do we dare that?
This might bump into FindPlasma.cmake, which is installed by kdelibs,
and should be removed: it applies to Plasma 4.1 only and bails out,
since after that, we used the KDE4 libs find_package foo. Now we're kind
of going back to pre-4.2 times. :-)