desktop-shell: Handle all other shsurfs

The output resize handler we only accounts for the background and panel
surfaces, so this handles all other regular shsurfs.

This patch would reuse any previously saved position, or reposition the
surfaces to avoid placing them outside of the output area. For maximized
or fullscreen type of surfaces, issue a new configure event to let
clients react to the new output dimensions.

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