Deprecate fullscreen shell and screen-share module

As part of migrating to kiosk shell and informing users that fullscreen is going away.

Patch series:

• removes zwp_fullscreen from clients and backend-wayland moved out to !1503
• adds deprecated-screenshare and deprecated-shell-fullscreen meson build options
• adds a dependency on deprecated-shell-fullscreen for deprecated-screenshareas that was not previously
• changes man pages to inform users that screen-share and fullscreen are deprecated including that screen share is not built by default and needs to be explicitly enabled

Note that probably worth while waiting on this one until the overlapping part is actually in the tree to have an alternative to screen-share.

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