Bug 897445 - Open search management prototype.

Adding an open search plugin from the browser:

![2013-07-30-22-39-29](https://f.cloud.github.com/assets/122602/884011/a4477180-f9a3-11e2-879b-70d7e93a5b9c.png)

Setting option to navigate to open search provider page:
![2013-07-30-22-39-19](https://f.cloud.github.com/assets/122602/884012/b42ffec8-f9a3-11e2-83b6-fbdc9f155252.png)

Simple management interface:
![2013-07-30-22-39-21](https://f.cloud.github.com/assets/122602/884016/bbd37c04-f9a3-11e2-817d-50b64e60d375.png)