ivi-shell: reference implementation of input panel for ivi-shell

- introduces ivi-shell/input-panel-ivi.c which is basically copied
  from desktop shell. It shall be improvaded to remove duplicate
  implementation.

Signed-off-by: Nobuhiko Tanibata <NOBUHIKO_TANIBATA@xddp.denso.co.jp>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>