Authentication section API KEY

[FielderMan]

Hello folks! In the authentication section of the API "TheHiveDocs/api/authentication.md" it is hinted that the API key is a form of authentication. However, I suggest it is rather a form of identification and it is TLS that is doing the authentication (if any).

I suggest that this section be revisited in order make it more clear what type of authentication (if any) is really performed within the API. This would make it easier to promote the project to nitpicky security professionals who read the docs.

Thanks for all the hard work!