util-linux: add menu items for login utilities

util-linux: add menu items for login utilities

This change extends to the login utilities the current policy of having
a selection item in the configuration menu for each utility that has an
--enable/--disable knob in the "configure" script:

- add selection items for login, runuser, su and sulogin (there was
  already an item for "last")
- move "login utilities" to Config.in.legacy
- make "login utilities" select last, login, runuser, su and sulogin

Signed-off-by: Carlos Santos <casantos@datacom.ind.br>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>