Add URL support
Similar to the URL in tryon, we could update the URL in sao to use the same syntax expect that it should not be the URL but just a hash part.
Sao should also listen for hashchange event to open the right tab (or show it if it already exist). This will also allow to support to navigate back in the history.
On login, sao must parse the hash to call the right action.
The URL should always show the hash of the selected tab.