Added naming conventions for definitions to naming.txt

Added naming conventions for definitions to naming.txt as discussed in the chat.

Thanks a lot for the PR! :)

I'm going to merge this and edit it a bit. For example, I actually couldnt find an example of an RA called somethingR, so I think this should just say "cameras" (so I was wrong when I claimed otherwise in the chat).

For the record, the chat conversation is at https://mattermost.mpi-sws.org/iris/pl/okiwdd83gingpqos3678w8xody.

mentioned in commit 68fed70f

merged