Update API docs in Herbie -- remove unused functions and improve docs

Looking at https://herbie.uwplse.org/doc/latest/api-endpoints.html

Be clear about which endpoints Odyssey uses, e.g., we don't use /exacts

Move other endpoints to Beta section

Add concrete values for each endpoint

For /translate, tell users to consider using FPBench 

Send questions to me and we should workshop to make sure a new reader has no questions