Minio Console Port (#188)

Added Added Minio console port. Default set to 8900 but subject to approval by the community. 
---
Fixes an issue where Minio show the following error in the logs and on opening localhost:9000 redirects to a random port.

```
WARNING: Console endpoint is listening on a dynamic port (41045), please use --console-address ":PORT" to choose a static port.
```
This PR allows one to access Minio dashboard on port 8900 and the API endpoint remains on port 9000. 

Example repo: https://github.com/SamuelMwangiW/sail-minio-example/

Author: SamuelMwangiW

stubs/minio.stub

@@ -2,14 +2,15 @@
         image: 'minio/minio:latest'
         ports:
             - '${FORWARD_MINIO_PORT:-9000}:9000'
+            - '${FORWARD_MINIO_CONSOLE_PORT:-8900}:8900'
         environment:
             MINIO_ROOT_USER: 'sail'
             MINIO_ROOT_PASSWORD: 'password'
         volumes:
             - 'sailminio:/data/minio'
         networks:
             - sail
-        command: minio server /data/minio
+        command: minio server /data/minio --console-address ":8900"
         healthcheck:
           test: ["CMD", "curl", "-f", "http://localhost:9000/minio/health/live"]
           retries: 3