Handle multiple token authorization setups

[bbockelm]

The SciTokens code was patched to consume multiple tokens, allowing an authorization configuration where a token from the cache is required -- but not used for filesystem access by the origin.

Upstream PR: xrootd#2397

[matyasselmeci]

Included in xrootd 5.7.3-1.5

[mwestphall]

Per instructions, needed to resolve a merge conflict when applying this on release v5.9.0
a0751f69e54b44c6e49e5ca191c2db923f27b7bf b251f92