batches: remove GraphQL deprecations
Created by: courier-new
[Just opening this as a draft to help scope out the removals.]
I did a sweep of both the BC schema file as well as the OSS one. I've removed all fields obviously marked for deprecation in our area and looked for anything else that seemed out-of-date, redundant, or otherwise deprecation-worthy, but outside of those fields we had already marked as deprecated, nothing stood out to me. So, good job team? 
Give the schema a browse and let me know if you think I missed something or want to make the case for deprecating something else! Otherwise I'll get into cleaning these up.
