r/minio-nginx: Reverse proxy for MinIO

The *minio-nginx* role configures nginx to proxy for MinIO.  It uses the
"subdomain" pattern, as described in [Configure NGINX Proxy for MinIO
Server][0]; the S3 API and the console UI are accessible through
different domain names.

[0]: https://min.io/docs/minio/linux/integrations/setup-nginx-proxy-with-minio.html

roles/minio-nginx/meta/main.yml

@@ -0,0 +1,7 @@
+dependencies:
+- role: minio
+  tags:
+  - minio
+- role: nginx
+  tags:
+  - nginx