Try to streamline 'quick start' documentation.
This should document really almost everything the user needs to do to get started with kdesrc-build.
The big thing missing is the .setup-env parts. I think that should go in kdesrc-build-setup but that's a separate discussion.
Also missing is discussion of --initial-setup, but then this
is meant to be the push that helps define what all goes into
--initial-setup. Once the documentation is accurate that should help in
determining which features to include in kdesrc-build to be able to make
this documentation even simpler, so that we can broaden the base of users
able to be productive with this and related tools.