shell: Introduce fullscreen and split role type of a surface

With it, this also adds two pending lists, for each role type and
aggregates the checks used to compare against the roles type when the
surface is being created. There's no functional at this stage.

Bug-AGL: SPEC-3334

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
Change-Id: I1900399fe35d9dbc26a93c374ac2f86efa860ba6