CLI Deploy: When pulling and a step changes name, offer to rename the file for me

[josephjclark]

If I've split my project out into files, and I pull from the app, and one my of step changes name, the sync will very cleverly track the changes into the correct local file on my filesystem.

But the step name is probably wrong now. If I have a step called Get Patients and I save it to patients.js, and then I rename the step to download data - the local step name will still be called patients.js.

If the CLI is smart enough to track the changes across the file, and it detects a name change, it should be able to at least warn the user that the step name has changed. Ideally it would auto-update the local filename too.

Note that the ability to generate a safe filename from a step name is common to #884