Bug/1079  - Workgroup not settable

Fixes [bug 1079](https://bugs.amahi.org/issues/1079) - **Workgroup not settable**.
```
The dashboard capability to change the Samba Workgroup is missing. It was previously located under Shares, Settings.
```

The ability to change the workgroup for shares was available in Amahi 6, but while transitioning from RJS to unobstructive JS in Amahi 7, this remained unimplemented. 

Solving this was very interesting. Got idea of how plugins and main apps are integrated. Also, figuring out the workflow of `SmartLinks` was slightly tricky, but it feels good to grasp it now.

![screenshot from 2014-03-06 21 28 48](https://f.cloud.github.com/assets/530850/2347024/61df3d18-a548-11e3-8176-f235ad1f2768.png)
![screenshot from 2014-03-06 21 28 57](https://f.cloud.github.com/assets/530850/2347026/66c77f34-a548-11e3-9a3a-45538aef32fa.png)
![screenshot from 2014-03-06 21 29 03](https://f.cloud.github.com/assets/530850/2347030/6dc412d4-a548-11e3-84a8-d63af842dacf.png)

Thank you @cpg for suggesting to give it a try. 

Cheers