feat: initial Nginx templates

conf.d/default.conf.template

@@ -0,0 +1,20 @@
+server {
+    listen 80 default_server;
+    server_name _;
+
+    return 404;
+}
+
+server {
+    listen 443 ssl default_server;
+    include snippets/https.conf;
+
+    server_name _;
+
+    return 404;
+}
+
+map $http_upgrade $connection_upgrade {
+    default upgrade;
+    ''      close;
+}