Add compatToRFC1132 utility

[NullVoxPopuli]

Please someone suggest a better name for this 🙈

In chatting with @RobbieTheWagner, it's become clear we do need to provide some utilities for interfacing with the old stuff, since we haven't shipped (and made everyone migrate to) the static/importable replacements for all the registry stuff just yet.

This utility works with @embroider/virtual/compat-modules and converts it to the strict format.

There is still work to make @embroider/virtual/compat-modules "somehow" detect when its being used with the strict module format in RFC 1132, but I don't know how to set that up atm, and I think this utility would be good regardless, as I think this library exposing a few conversion utilities would be good.

After this PR, there are also planned:

• pods support: https://github.com/ember-cli/ember-strict-application-resolver/pull/13/files#diff-5a682fb30ffcaacbdb11ef2204237c67b238eed93fd2eae3757a3d06179921f5R15 -- which should just find all the pods patterns and convert them to RFC 1132 format
• lookupToModulePath (e.g.: service:main becomes ./service/main)
• modulePathToLookup (e.g.: ./service/main becomes service:main)

(all 3 for separate PRs)

[NullVoxPopuli]

This will no longer be needed as we're going to make compat-modules support emitting ./ for the default module prefix