Move qdoc into qtbase and bootstrap it

Move qdoc into qtbase and bootstrap it

We need qdoc in qtbase to be able to properly
modularize our documentation and build it
when building the different Qt modules.

qdoc does contain a copy of the qml parser from
qmldevtools, but this is the lesser evil compared
to how we are currently forced to genereate our
docs (and the fact that no developer can run
qdoc and check the docs for their module).

Change-Id: I9f748459382a11cf5d5153d1ee611d7a5d3f4ac1
Reviewed-by: Casper van Donderen <casper.vandonderen@nokia.com>
Reviewed-by: Martin Smith <martin.smith@nokia.com>