View team account's Newsfeed as team member (BB-10029)

A team member should have a way of viewing the team's Newsfeed in the web UI.

Right now, the only way I can see the team account's newsfeed is to log out as myself and log in under the team account.

I can, of course, grab the RSS URL of the team account's Newsfeed and stick that in an RSS reader, and that is my workaround for now. I can also go and follow every repository in the team account, but that just undermines the readability of my own Newsfeed.

When I browse to the team account as a team member, there should be some page that displays the team's Newsfeed.

Or, even better, on my own dashboard page, there perhaps could be a toggle for switching between my Newsfeed, and the Newsfeeds of the team accounts of which I am a member.