Update Rafiki docs diagrams since making auth optional

[JoblersTune]

Since making auth optional in Rafiki Admin, the localenv architecture diagram is probably not the correct place to detail Rafiki Admin's auth setup since it is disabled there by default.

It might make more sense to update the main Rafiki architecture diagram instead

And then remove the Kratos and Mailslurper components from the localenv environemnt overview diagram

This is just a suggestion and a note for the team and doc writers to keep track of this as the docs get updated.