Feature proposal: --no-clobber option for the copy command

[MindaugasLaganeckas]

In our usecase, we would like to have an option to NOT overwrite the already existing files.
I would like to propose a new action option, called no_clobber: false(default)/true.
The interpretation of it would be: do not overwrite an existing file
If you are also interested in such feature, than I could start working on the PR.

[andstor]

Hi!

I am definitely interested in getting such feature implemented. Although, I think this is a rather special use case. It would therefore be very interesting in learning more about your use case.

Anyhow, contributions like this is very welcomed 🙏