nginx-nodejs-redis: add dev envs config

* Add Docker Desktop Development Environments config
* Upgrade NodeJS image
* Rename `nginx` to `proxy` and use bind mount for config
  for consistency with other examples

Signed-off-by: Milas Bowman <milas.bowman@docker.com>

nginx-nodejs-redis/proxy/nginx.conf

@@ -0,0 +1,12 @@
+upstream loadbalancer {
+  server web1:5000;
+  server web2:5000;
+}
+
+server {
+  listen 80;
+  server_name localhost;
+  location / {
+    proxy_pass http://loadbalancer;
+  }
+}