kate: add project generator for the Kate project plugin

This patch adds an extra generator for KDE's kate text editor,
or better more specifically, the project plugin.

Alex
kate generator: insert build targets

This can be used by the build plugin in kate.
Code is quite similar to the one for Eclipse.

Alex
kate: add some documentation

Alex
Merge topic 'KateProjectGenerator2' into next

c8ac63c kate: add some documentation
1766185 kate generator: insert build targets
4757385 kate: add project generator for the Kate project plugin