Check list of models in the main README and sort it
# What does this PR do?

In our effort to have the repo consistency check catch all potential mistakes a contributor can make when adding a new model, this PR adds a new script to make sure all added models are also put in the main README. As a bonus, it also enforces that said README is sorted in alphabetical order cause that's prettier.

Some models are not supposed to be in the main README, so there is a new list for those black sheeps. Some models have different names in the main README and in the lib, there is a map for that.

MobileBERT and RAG were not in the README and I think they should o I added them, the other absent do not have a paper from what I checked. I fixed typos (usually in casing) as well.
_The documentation is not available anymore as the PR was closed or merged._