The org.logdiag ID has been chosen as I haven't found any specific rules
and com.github.logdiag seems not to be future-proof. This domain remains
available so far, anyway.
The schemas are compiled only when installed directly to CMAKE_INSTALL_PREFIX
to the root filesystem. When invoking `make install` with DESTDIR, only
the XML files are copied over as the schemas would have to be recompiled
later anyway.
