SOFTWARE-6141: first pass at origin authZ validation config

[brianhlin]

The post-joining the federation validation still needs to be fixed up but I don't have time before heading off on vacation. I think that we should probably merge the two validation sections and just note the -c <ORIGIN HOSTNAME>:<ORIGIN PORT> flag in a note or something.

[brianhlin]

@matyasselmeci please run with this while I'm on vacation next week

[matyasselmeci]

Thanks for getting started with this. I will poke the developers about the use of the -c flag for testing the origins; on one hand, testing the origin server's functionality before joining the federation is thing we want to be able to do, and it's nicer to have a first-class Pelican way to do it instead of relying on curl; on the other hand, -c is short for --cache so using it to test origins feels like a misuse.

[brianhlin]

@matyasselmeci IIRC, we got the go ahead during a Pelican meeting to use -c

[matyasselmeci]

Yeah, I think we briefly talked about renaming it from --cache but haven't settled on a new name.

[matyasselmeci]

LGTM. I'm working on updating this on #291 as well; I'll rebase that on this.