feat: copy to both clipboard and primary on wayland

[paulfariello]

copy/paste action on wayland clipboarder allow for copying to both clipboard and primary.

Add the exact same behavior to the copy action.

[fdw]

This is the same behavior as for xsel and xclip. Is there a reason you want it in both clipboards?

[paulfariello]

@fdw yes the same behavior as for xclip. The main workflow is when copying for pasting in a terminal with middle click (so from the principal clipboard). When doing the copy rofi doesn't know where the user want to paste so it seems ok to copy in all "selection".

[fdw]

I meant that currently, all clipboarders only use the primary keyboard. If we change that, it should be for all of them.

Also, please let me think if I want to hide this behind a configuration. It seems a bit destructive to change both clipboards.

[fdw]

Sorry, I've been quite busy (and expect to stay that way, too). To make some progress, could you please update the other clipboarders to use the same mechanism as well?
Then it's only a matter of adding a configuration switch if desired, and I can do that later.