implement a few words of reporting from the mdm-update command as it's in progress, so that when doing an update on a project with a lot of dependencies, there's a pulse visible.

at the start of each dependency submodule's update, a line with the name and the n-of-m count is printed.  these lines overwrite each other as they go; if a repo has 100+ dependencies, I don't wanna hear about it unless they've changed.

progress bars for actual percent work within a single fetch is future work.