This makes the haproxy role more generic so we can run another (or
potentially even more) haproxy instance(s) to manage other services.
The config file is moved to a variable for the haproxy role. The
gitea specific config is then installed for the gitea-lb service by a
new gitea-lb role.
statsd reporting is made optional with an argument. This
enables/disables the service in the docker compose.
Role documenation is updated.
Add new IP addresses to inventory for the rebuild, but don't
reactivate it in the haproxy pools yet.
Note this switches the gitea testing to use a host called gitea99 so
that it doesn't conflict with our changes of the production hosts.