It was inconsistent to access projects administration from the top-level
Projects menu item and, at the same time, have to go to Admin > Groups
or Admin > Plugins to access the Groups or Plugins administration.
This change also removes the top-level Admin menu as it becomes
unnecessary once the Groups and Plugins are moved to the top-level.
Change-Id: Ia58b768317a1998165d782d81952552b5395cbc6
Signed-off-by: Sasa Zivkov <sasa.zivkov@sap.com>