r/victoria-metrics-nginx: Add reverse proxy for V-M

The *victoria-metrics-nginx* role configures *nginx* as a reverse proxy
for Victoria Metrics.

roles/victoria-metrics-nginx/templates/victoria-metrics.nginx.conf.j2

@@ -0,0 +1,10 @@
+server {
+    listen 443 ssl http2;
+    listen [::]:443 ssl http2;
+    server_name {{ victoria_metrics_server_name }};
+
+    location / {
+        proxy_pass http://[::1]:8428/;
+        client_max_body_size 100m;
+    }
+}