Add Shift+Print keybinding to trigger 'mate-screenshot --area' for
interactive area selection. This gives users a dedicated keybinding for
area screenshots in addition to the existing Print (screen) and
Alt+Print (window) shortcuts.

Fixes mate-desktop/marco#157

This prevents race conditions with applications like mate-screenshot
that need to grab input (e.g. for area selection).

Fixes mate-desktop/mate-utils#37

Extend MetaFrameBorders to include shadow and resize borders to
calculate invisible border size. Also added border caching to prevent
recalculating borders on every frame operation.

This is a backport of the following commits from Metacity:
- https://gitlab.gnome.org/GNOME/metacity/-/commit/21e664af
- https://gitlab.gnome.org/GNOME/metacity/-/commit/3c6e269b
- https://gitlab.gnome.org/GNOME/metacity/-/commit/700e87ea

Adds GNOME3-style dynamic workspace management. Workspaces are created
when no empty ones exist and removed when multiple empty workspaces are
present, maintaining exactly one empty workspace at the end.

Fixes #406

Adds support for configurable mouse actions on window titlebars,
including middle-click and scroll wheel events.

New actions added:
- close: Close the window
- raise: Raise window to top
- toggle_stick: Toggle sticky state (all workspaces)
- toggle_above: Toggle always-on-top state

Fixes #425
Fixes #787

Note: requries matching mate-control-center changes to work properly

In systems with bamfdaemon running, windows get this property for
finding the dekstop spec file of an application. This can be used to
find the defined icon for any application window that reports this
attribute and provider much better icon matching.

Looking up GDesktopAppInfo from the GTK Application ID we can get a much
better match for the icon and load it at the appropriate scale. This
results in matching icons to straneous windows and better looking icons
overall.

Enabling code that is supposed to be used in compositing conditions is
harmful if compositing is not actually available. Just checking the
preference is not enough to make sure that compositing is available -
the X server might be missing crucial extensions for compositing to
work, which in turn correctly disables the internal compositor.

The end result is graphical issues like black borders around windows in
such situations.

Make sure that compositing is both requested AND available to fix this
bug.