Rucio replica sorting service using geolocation

[ponyisi]

This uses functionality added to the DID finder library (ssl-hep/ServiceX_DID_Finder_lib#34) to sort replicas for the Rucio DID finder. In principle a similar pattern can be implemented for other DID finders, though none of the others provide multiple replicas at the moment.

[BenGalewsky]

@ponyisi will you replace this PR with a simplified one that is just implemented in the Rucio DID finder?

[ponyisi]

I will "un-draft" this once the DID finder library is updated and I don't have to point at a git branch any more... but I've verified it works OK.

[ponyisi]

Resolves #766

[BenGalewsky]

@ponyisi -- looked at the code in the DID Finder Library - Given the YAGNI principle I would prefer that we implement this in the Rucio DID finder to start with. We are going to find problems and enhancements and fixing things in the library is a drag.

I would prefer to see this initial implementation entirely done in the Rucio DID Finder and then we can move it to the library once we find a use case for that.

[ponyisi]

@BenGalewsky whatever's needed to get this in ... it's rather desperately needed....

[BenGalewsky]

Thanks for the changes. I think we have different ideas about code clarity, but this should be ok to maintain