document in README how to set up the front controller on DDEV / Nginx

Problem/Motivation

We should document this as many people use DDEV locally.

I've got this working by adding a file `.ddev/nginx/statistics.conf` containing:

location /modules/contrib/statistics/statistics.php {
  fastcgi_split_path_info ^(.+\.php)(/.+)$;
  fastcgi_pass unix:/run/php-fpm.sock;
  fastcgi_buffers 16 16k;
  fastcgi_buffer_size 32k;
  fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
  fastcgi_param SCRIPT_NAME $fastcgi_script_name;
  fastcgi_index index.php;
  include fastcgi_params;
  fastcgi_intercept_errors off;
  # fastcgi_read_timeout should match max_execution_time in php.ini
  fastcgi_read_timeout 10m;
  fastcgi_param SERVER_NAME $host;
  fastcgi_param HTTPS $fcgi_https;
  # Pass the X-Accel-* headers to facilitate testing.
  fastcgi_pass_header "X-Accel-Buffering";
  fastcgi_pass_header "X-Accel-Charset";
  fastcgi_pass_header "X-Accel-Expires";
  fastcgi_pass_header "X-Accel-Limit-Rate";
  fastcgi_pass_header "X-Accel-Redirect";
}

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes