feat: centralize nginx TLS and proxy defaults

conf.d/10-defaults.conf.template

@@ -0,0 +1,19 @@
+http2 on;
+ssl_protocols TLSv1.2 TLSv1.3;
+ssl_session_cache shared:SSL:10m;
+ssl_session_timeout 10m;
+
+server {
+    listen 80 default_server;
+    listen [::]:80 default_server;
+    server_name _;
+
+    return 404;
+}
+
+server {
+    listen 443 ssl default_server;
+    listen [::]:443 ssl default_server;
+
+    ssl_reject_handshake on;
+}