Add various polish to Conduwuit

https://github.com/Virkkunen and I have been working on the same feature
simultaneously.

This patch adds my additional independent work on top of his changes.

Notable changes here compared to Virkkunen's original work:

- renaming config-related variables (`matrix_conduwuit_*` ->
  `matrix_conduwuit_config_*`). This is consistent with other roles (and
  better), but deviates from how the Conduit role was implemented.

- using a full configuration sample from https://conduwuit.puppyirl.gay/configuration.html
  instead of using the old Conduit config file template

- introducing configurability for more Conduwuit config settings, to support easy registration, etc.

- removing configuration settings that Conduwuit does not support
  anymore (e.g. `max_concurrent_requests`)

- cross-linking docs pages for Conduit and Conduwuit

- a Conduwuit docs page which is much improved compared to the old
  Conduit one

- REAMDE updates

roles/custom/matrix-conduwuit/templates/systemd/matrix-conduwuit.service.j2

@@ -1,6 +1,6 @@
 #jinja2: lstrip_blocks: "True"
 [Unit]
-Description=Conduwuit Matrix homeserver
+Description=conduwuit Matrix homeserver
 {% for service in matrix_conduwuit_systemd_required_services_list %}
 Requires={{ service }}
 After={{ service }}
@@ -21,10 +21,10 @@ ExecStartPre={{ devture_systemd_docker_base_host_command_docker }} create \
 			--read-only \
 			--tmpfs=/tmp:rw,noexec,nosuid,size={{ matrix_conduwuit_tmp_directory_size_mb }}m \
 			--network={{ matrix_conduwuit_container_network }} \
-			--env conduwuit_CONFIG=/etc/matrix-conduwuit/conduwuit.toml \
+			--env CONDUWUIT_CONFIG=/etc/conduwuit/conduwuit.toml \
 			--label-file={{ matrix_conduwuit_base_path }}/labels \
-			--mount type=bind,src={{ matrix_conduwuit_data_path }},dst=/var/lib/matrix-conduwuit \
-			--mount type=bind,src={{ matrix_conduwuit_config_path }},dst=/etc/matrix-conduwuit,ro \
+			--mount type=bind,src={{ matrix_conduwuit_data_path }},dst=/var/lib/conduwuit \
+			--mount type=bind,src={{ matrix_conduwuit_config_path }},dst=/etc/conduwuit,ro \
 			{% for arg in matrix_conduwuit_container_extra_arguments %}
 			{{ arg }} \
 			{% endfor %}