Disentangle auto modules from other modeling files
# What does this PR do?

This PR cleans up the auto modules to have them rely on string mappings and dynamically import the model when they are needed, instead of having a hard dependency on every modeling file.

There is no breaking changes are all the MAPPING classes are still present and will behave like regular dictionaries, just loading the objects as needed. On the internal tooling side, this allows us to remove the script that was extracting the names of the auto-mapping (since we have them now) and the file that stored them.