`mv`: expose main functionality for nushell

[tertsdiepraam]

Part of: nushell/nushell#10446

nushell wants access to our mv internals. Which means exposing the exec function and Behavior struct. Feel free to rename those to something more sensible for a public API (e.g. move & Options, to match the naming scheme from cp). There should be documentation for all the public items in the API as well.

This is an excellent first issue: feel free to claim this!

We did the same thing for cp already. You could use that PR as a guide: #5152

[kaathewisegit]

While rm refactoring is being discussed, I wanted to take on this issue.

I noticed mv uses a Behavior struct for options, whereas other commands use Options. Would it be fine to change its name to Options in the PR?

[tertsdiepraam]

I think @PThorpe92 was working on this, but didn't mention that here yet. In the meantime, you could try to look at other utils. For example, the ones mentioned here: #5088 (comment). In general though, I think it's nice to make all utils as uniform as possible and I do encourage renaming as part of these PRs. Though more involved refactors should be done separately.

[PThorpe92]

Yeah I'll have a PR in today on this.

[kaathewisegit]

Got it!