Move description of the purpose of the file before any definition.

One empty line between related enum definitions.

All typedefs before all structs.  This is exception from the usual, but not the
only one, we already have something similar for some other structs.  This way we
can move contents between structs and reorder some parts nicely without moving
all definitions of one type before another one just so it's defined.

Define all classes in one place.

Have one initialization function for all classes in the file.
Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>