Control file cloning option directly from the Copy/Move dialog

[tuffnatty]

Proposed changes

Add a checkbox to control the file cloning option to the Copy/Move dialog.

I believe it improves both discoverability and predictability of the option.
The documentation already mentions the option in the Copy/Move dialog section.

Checklist

• I have referenced the issue(s) resolved by this PR (if any)
• I have signed-off my contribution with git commit --amend -s
• Lint and unit tests pass locally with my changes (make indent && make check)
• I have added tests that prove my fix is effective or that my feature works
• I have added the necessary documentation (if appropriate)

[mc-worker]

I think it's unnecessary. I think most users don't care about internals of copy process.

[tuffnatty]

I think it's unnecessary. I think most users don't care about internals of copy process.

I believe the opposite (although I don't have any statistically significant data to prove it as well). That is, I believe that mc, as well as other "orthodox 2-panel file managers" (OFM), has lost its value for most non-power users when GUIs has taken their place, and since that moment mc is mostly a power user's tool. And a power user's tool should (IMHO) have its settings well exposed.

Another thing is that I (and probably many others) don't consider zero-copy cloning the same operation as plain copy. AND I would like to be able to do both, without having to look up the setting in menus.

For the reference, far2l, the only other console OFM providing this functionality, has this setting in the Copy dialog.