Recommend AVM if a custom module is very similar

This definitely has a potential to be noisy if you don't want to use AVM for whatever reason, so if we were to implement something like this we should have the ability to turn it off.

TODO: Need to come up with an algorithm for identifying "similar" code blocks and/or modules

No files, tests, or entry points are named. Start by defining an algorithm for identifying similar custom modules or code blocks and decide how recommendations can be disabled. Done means the similarity behavior and opt-out requirements are specified well enough for implementation.

Written by the indexing model from the issue text.