Initial work on matrix-homeserver-proxy role and eliminating matrix-nginx-proxy

This is still very far from usable.

Various bridges and bots are still talking to
`matrix-nginx-proxy` instead of the new `matrix-homeserver-proxy` role.
These services need to be reworked. While reworking them,
various cleanups are being done as well as adding Traefik-labels to
those that need them.

roles/custom/matrix-homeserver-proxy/templates/nginx/conf.d/nginx-http.conf.j2

@@ -0,0 +1,13 @@
+#jinja2: lstrip_blocks: "True"
+# The default is aligned to the CPU's cache size,
+# which can sometimes be too low.
+# Thus, we ensure a larger bucket size value is used.
+server_names_hash_bucket_size 64;
+
+{% if matrix_homeserver_proxy_http_level_resolver %}
+resolver {{ matrix_homeserver_proxy_http_level_resolver }};
+{% endif %}
+
+{% for configuration_block in matrix_homeserver_proxy_http_additional_server_configuration_blocks %}
+	{{- configuration_block }}
+{% endfor %}