added clipboard support

[niminypiminy]

added copy, cut, paste to domeventdata and domeventkind
added keyboard shortcuts, copy, cut, paste
enabled wayland-data-control feature for arboard
added new ui events
integrated with shell....

tested on linux. works with keyboard shortcuts.
did not test on windows or macos.

[niminypiminy]

for the other operating systems, I suspect you will need to drop the wayland-data-control feature. perhaps something like

[target.'cfg(not(target_os = "linux"))'.dependencies]
arboard = "3.6.1"

[target.'cfg(target_os = "linux")'.dependencies]
arboard = { version = "3.6.1", features = ["wayland-data-control"] }