Drop lib/neutron module

Module lib/neutron was introduced long time ago as new module to deploy
neutron. It was intended to replace old lib/neutron-legacy module. But
since very long time it wasn't really finished and used by anyone and
lib/neutron-legacy is defacto standard module used by everyone to deploy
neutron with devstack.
In [1] unfinished lib/neutron was deprecated and now it's time to remove
it from the devstack code.

This patch also renames old "lib/neutron-legacy" module to be
"lib/neutron" now.

Previously "old" lib/neutron-legacy module was accepting neutron
services names wit "q-" prefix and "new" lib/neutron module was accepting
services with "neutron-" prefix. Now, as there is only one module it
accepts both prefixes.
For historical reasons and to be consistent with old lib/neutron-legacy
which was widely used everywhere, services will be named with "q-"
prefix but both prefixes will be accepted to enable or disable services.

This patch also moves _configure_neutron_service function to be called
at the end of the "configure_neutron" after all agents and service
plugins are already configured.

[1] https://review.opendev.org/c/openstack/devstack/+/823653

Related-bug: #1996748

Change-Id: Ibf1c8b2ee6b6618f77cd8486e9c687993d7cb4a0

clean.sh

@@ -50,7 +50,6 @@ source $TOP_DIR/lib/placement
 source $TOP_DIR/lib/cinder
 source $TOP_DIR/lib/swift
 source $TOP_DIR/lib/neutron
-source $TOP_DIR/lib/neutron-legacy
 
 set -o xtrace