Allow serving app from non-root path in dev env

Usage:

$ EXTRA_SOURCES_ANSIBLE_OPTS='-e ingress_path=/awx' make docker-compose
$ curl http://localhost:8013/awx/api/v2/ping/

tools/docker-compose/nginx.conf

@@ -1,31 +0,0 @@
-worker_processes  1;
-
-error_log  /var/log/nginx/error.log warn;
-pid        /var/run/nginx.pid;
-
-events {
-    worker_connections  1024;
-}
-
-http {
-    include       /etc/nginx/mime.types;
-    default_type  application/octet-stream;
-    server_tokens off;
-
-    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
-                      '$status $body_bytes_sent "$http_referer" '
-                      '"$http_user_agent" "$http_x_forwarded_for"';
-
-    access_log  /var/log/nginx/access.log  main;
-
-    map $http_upgrade $connection_upgrade {
-        default upgrade;
-        ''      close;
-    }
-
-    sendfile        on;
-    #tcp_nopush     on;
-    #gzip  on;
-
-    include /etc/nginx/conf.d/*.conf;
-}