Guard against accidental deletion of external DB

[MasterAM]

This is still untested. This is my draft for a feature meant to prevent unintended deletion of a production databases.

I am using the mongodb-uri package for completeness (and it is also used by Meteor, so while it remains in the same version I believe that Meteor will normalize the dependency). Searching for localhost using a RegEx might also work is a weaker test, but mine might be an overkill.

I should add the '127.0.0.1' case as well if we use the current method.

What do you think?