Move xdg-shell and xwayland-shell surfaces to new API

Also render alt-tab on-screen-display by converting cairo-surface to
wlr_buffer

Dump view_tree and osd_tree on calling debug-action. Example bind:

<keybind key="A-F12">
  <action name="Debug"></action>
</keybind>

Remove buffer_drop() and just destroy it.

...rather than free(buffer->data)

We need it for wlr_scene_layer_surface_v1_create()

Future meson releases will change the default, so we explicitly set
check: false to maintain behaviour

...to make it easier to deal them separetely from layer-shell popups

This excludes popups.

desktop.c move_to_front() calls wlr_scene_node_raise_to_top
desktop.c, ssd/include.h add LAB_SSD_{OSD, MENU, LAYER_SURFACE} enums
desktop.c desktop_surface_and_view_at() -> desktop_node_and_view_at()
cursor.c reenable cursor_rebase()
cursor.c reenable button click on layer surface

This prevents segfaulting when unminimizing

Use wlr_input_device from input device base.
Use wlr_keyboard where possible.

...in order to sync resize/move events to avoid left/bottom edge wobbling
when resizing with top/left resize edges

Instead use view->{w,h} which are set on client commit

Prevents a single action like ToggleDecorations + ToggleMaximize to
position the view somewhere with negative coordinates when unmaximizing.

It may still position the view on negative coordinates but later commit
events will fix the position. This issue only exists on xwayland because
there are no configure serials which we could use to ignore all
repositioning until we are at the latest desired state.

Instead, just tag the struct so we can reference it.

Support identification of wlr_scene_node role to enable simplification
of codebase including the avoidance of iterating over lists of
layer-surface, menuitems, and so on.

Use node-descriptors for xdg toplevels and popups

Discovered when right-clicking names in hexchat

Because we like to start public function names with the name of the
file.

Move prototype from labwc.h to layers.h

Fixes "a label can only be part of a statement
and a declaration is not a statement".

...in anticipation of adding helpers like node_view_from_node()

Support returning the following structs:
  - view from LAB_NODE_DESC_VIEW or LAB_NODE_DESC_XDG_POPUP
  - lab_layer_surface form LAB_NODE_DESC_LAYER_SURFACE
  - lab_layer_popup from LAB_NODE_DESC_LAYER_POPUP

...to show popups when using @Consolatis's example panel

https://github.com/Consolatis/wl_framework

This allows popups to be rendered above views and other layers. Without
this, the popups of a layer-shell application in the bottom layer would
render below views, which does not seem right. For example, consider the
case of a panel with right-click popups.

Include <wlr/interfaces/wlr_buffer.h>

https://gitlab.freedesktop.org/wlroots/wlroots/-/commit/39b68ea47a661b1f7562ce283652de08f222b2be

Raise border on top of (z-order) titlebar

To avoid incorrect view position, for example on initial placement.