Several legacy jobs use the OVERRIDE_ENABLED_SERVICES variable
from d-g so set the list of services that should be enabled and
ignore the default set calculated via the feature matrix.
Add support for a similar functionality in the zuulv3 jobs
using the 'disable_all_services' localconf function.
Change-Id: I690554ec62cef3be600054071efbb3f92a99249e
5551170ad3