Update Snap Status link

The 'Snap Status' link doesn't link to [microstack](https://snapcraft.io/microstack) in the snapcraft store. Also, it would look better to have that link attached to a snap store logo like this one.
![snap](https://user-images.githubusercontent.com/45159366/54247177-27633480-44f5-11e9-93b0-81041e8ad435.png)
