[FEATURE] Add OS-default keyboard shortcuts for copy/paste in TabnineChat

[pgib]

Is your feature request related to a problem? Please describe.

Copying from and pasting to the system clipboard is only available via the contextual menu. I should be able to use Command-c/Command-v (Mac) or Ctrl-c/Ctrl-v (Windows/Linux) to access these functions like any other app would allow.

Describe the solution you'd like

Add default shortcut keys to these basic, system-level functions.

Describe alternatives you've considered

N/A

Additional context

[amirbilu]

should be fixed by #200

[ckob]

Hi @amirbilu, I've just tested it still not work for me. Can't copy or paste with the keyboard shortcuts. I'm on MacOS using the latest 13c957d plugin commit. Configured as enterprise self hosted.
Thanks