Doc: Adding qtdeclarative documentation configuration files.

We need a modularized Qt Quick documentation package that only
contains Qt Quick 2.

Add a make target for the documentation.
Copied Qt 5's offline style as a starting CSS template.

Change-Id: I2298f23c7695ebbe38f43b89626431a2e8059a9a
Reviewed-on: http://codereview.qt-project.org/5891


Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Alan Alpert <alan.alpert@nokia.com>