Init workspace browser view in time

It needs to initialize `browserView` before any possible trying to open a file. But we can get `browserView` workspaces only being logged in. So initialize it right after successful login.
In NWK this initializing will never be and it's redundant. So stop using it in NWK
@marimano - No need to add the additional trigger.  Just do:
```
this.model.login.on('change:isLoggedIn', this.viewBrowser, this );
```