The "External feeds" tab looked a bit empty with just the External
Feeds block. We now have enough blocks to make it worthwhile to
have a tab for them: externalvideo, externalfeed and googleapps.

Change-Id: I193240f6a16c0081625d2180599047ea5fcee00a
Signed-off-by: Francois Marier <francois@catalyst.net.nz>