This change matches an earlier modification to os_neutron
Currently we symlink /etc/<service> to empty directory at pre-stage,
and filling it with config only during post_install. This means,
that policies and rootwrap filters are not working properly until
playbook execution finish. Additionally, we replace sudoers file
with new path in it, which makes current operations impossible for
the service, since rootwrap can not gain sudo privileges.
With this change we move symlinking and rootwrap steps to handlers,
which means that we will do replace configs while service is stopped.
During post_install we place all of the configs inside the venv,
which is versioned at the moment.
This way we minimise downtime of the service while performing upgrades
Closes-Bug: #2056180
Change-Id: I9c8212408c21e09895ee5805011aecb40b689a13