[m-rev.] for review: move file copying to its own module

[Julien Fischer]

On Fri, 5 Jan 2024, Zoltan Somogyi wrote:

> On 2024-01-05 16:47 +11:00 AEDT, "Julien Fischer" <jfischer at opturion.com> wrote:
>>
>> For review by anyone.
>>
>> This diff just shifts code about; the request for review is for the new module
>> name, documentation etc, plus the following proposal, which outlines the next
>> changes I am intending to make.
>
> We normally use _util as a module name component when there are several
> utility predicates/functions in a module. In this case, there is only one. Is there
> a realistic chance of another being added in the foreseeable future? If yes, then
> the name copy_util is fine. Otherwise, I would just name the module copy_file,
> since it is more descriptive.

There's a fairly strong chance that the directory copying code is also
going to end up there. We can rename it a later date if that doesn't end
up being the case.

Julien.