consolidate ssl-params and proxy_params

Signed-off-by: Arthur Lu <learthurgo@gmail.com>

snippets/ssl-acme.conf

@@ -0,0 +1,5 @@
+# letsencrypt validation
+location '/.well-known/acme-challenge' {
+	default_type "text/plain";
+	root /var/www/html;
+}