Add Dockerfile and supervisord for PHP deployment

nginx.conf

@@ -1,10 +1,10 @@
 upstream php {
-    server unix:/tmp/heroku.fcgi;
+    server unix:/var/run/php/php8.1-fpm.sock;
 }
 
 server {
     listen 8080;
-    root /app;
+    root /var/www/html;
     index index.php index.html;
 
     # Block access to hidden files and directories
@@ -49,7 +49,7 @@ server {
 
     # Static assets for pancake/third_party
     location /pancake/third_party {
-        alias /app/pancake/third_party;
+        alias /var/www/html/pancake/third_party;
         expires 1y;
         add_header Cache-Control "public, immutable";