Running -j8 for all make invocations regardless of which is a good way
to cause spectacular failures in installcheck-world testing, so remove
the setting. Also remove the link to workstation-setup repo as it's not
helpful for non-Pivotal hackers.
Reviewed-by: NJacob Champion <pchampion@pivotal.io>

Update README based on feedback from a new developer to the GPDB codebase

[ci skip]
Co-authored-by: NJim Doty <jdoty@pivotal.io>
Co-authored-by: NKevin Yeap <kyeap@pivotal.io>

The correct order is as follows:
1. modify ~/.bash_profile
2. ssh to localhost
3. make create-demo-cluster

See https://github.com/greenplum-db/gpdb/issues/3704 for more detail

Prior to this change, make create-demo-cluster would fail since the
command line could not find pip.

Signed-off-by: NBen Christel <bchristel@pivotal.io>