[FEATURE] #111 Add menu item "Add Account..." to Saros menu

Change-Id: I17e5035d34a4698467f3ca36cf0f3651368d01de
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1280
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>