Glossary: Add OpenDev, update Zuul
Glossary: Add OpenDev, update Zuul

Add an entry for OpenDev - copied mainly from https://opendev.org/ and
update the entry for Zuul.

Change-Id: Ib1d49074ec0ae6ca583ad354e36a02c4125f3af5

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals