baloo kf5 by default

[Jonathan Riddell]

New trello item https://trello.com/c/bHts0dQn/71-consider-using-baloo-kf5-by-default

Upstream advises using baloo kf5 version even with Plasma 4 and KDE SC 4 Software as it has fewer bugs and is faster, consider if we should do this

- check it upgrades
- check it works with kdelibs4 and kf5 software
- check size of image
- rename baloo 4 sources

comments welcome

Jonathan