Initial commit

This is based on phosh commit 016036f67aa2a0b6b375495b8ab21369dbd77288
plus the changes from the osk-vk branch:

  phosh-osk-stub: Add keyboard widget

  This adds a minimal keyboad widget. It supports popovers for additional
  characters and can parse gnome-shell's keyboard layouts to generate
  popovers.

  This took inspiration from virtboard (keymap), squeekboard/eekboard (for
  rendering), gnome-shell's OSK for layout parsing.

  The keyboard layouts were taken from gnome-shell as of
  6a88c0f0be5aed836f33ed2989d33add58c01403

Signed-off-by: Guido Günther <guido.gunther@puri.sm>