Merge pull request superfly#15 from superfly/multi-sso

allow auth.DischargeRequest to contain multiple identities

hack: put more data in auth.DischargeRequest

attestations for auth'ed user

maintain go 1.20 compatability

move scope helpers from other repo

clusters belong to the litefs-cloud feature, not directly to orgs

flyio: add NoAdminFeatures caveat

allow full location to be passed to tp.Client auth helpers

tp.Client option for ignoring certain third parties

another tp.Client helper for Authorization header