Add init step that creates initial admin user for developer system

The new init step automatically creates the first administration user
if development_become_any_account is chosen as auth type. This allows
to fully script the setup of a test system.

Change-Id: Id3b78218306c8d29116905226850d96a421e5440
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>