Create a proper "deprecate/move" function

[uliska]

Now that snippets is under oll-core control we should have a better way to move modules around, or rather to notify the user about that fact (instead of risking hard-to-track errors).

Some mapping of moved modules may be stored and checked upon module loading.

This would print an informative warning message and load the alternative module instead.

The only thing this wouldn't cover is that the alternative package must be available