xfwm4-wayland changes

Here are the latest changes for xfwm4-wayland:

- Merge patch to fix SSD windows displaying as empty frames

- Merge patch to fix crash when opening window with no title

- Rename compositor binary to xfwm4-wayland

- Fix crash when using pixman renderer

- Merge the original X11 version of xfwm4 and the shell helper client for the Wayland version (xfwm4-wayland-shell) into the same binary. This binary is now called "xfwm4". This should mean that the original X11 version of xfwm4 has now been ported to the meson build system. I haven't tested it on X11 though.

- Keyboard shortcuts are now kinda configurable? Though it currently only works for the alt-tab switcher, and the only modifier key it recognises is Alt.

Git repository:
https://github.com/adlocode/xfwm4/tree/wlroots

Regards
adlo