Switching from doing "post-start" loop hacks to running the container
in 3 steps: `create` + potentially connect to additional networks + `start`.
This way, the container would be connected to all its networks even at
the very beginning of its life.

* add prometheus-nginxlog-exporter role

* Rename matrix_prometheus_nginxlog_exporter_container_url to matrix_prometheus_nginxlog_exporter_container_hostname

* avoid referencing variables from other roles, handover info using group_vars/matrix_servers

* fix: stop service when uninstalling

fix: typo

move available arch's into a var

fix: text

* fix: prometheus enabled condition

Co-authored-by: ikkemaniac <ikkemaniac@localhost>

Fixes https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/2090