bug#43153: Add new command project-find-dir (and move binding of project-dired)

[Juri Linkov]

>> BTW, I have such customization:
>>    (define-key project-prefix-map "V" vc-prefix-map)
>> to allow vc commands in a project, e.g. 'C-x p V D' for 'vc-root-diff'.
>
> Hmm. I'm not sure when I'd use it instead of the shorter 'C-x v D'.
>
> When you are inside a Git submodule, maybe? It can make a difference. But
> then you have to be aware that the diff will not include changes in the
> submodules (just the changed summary hashes).

I meant that 'C-x p V D' can be typed outside of a repository
to select a project.