Merge branch 'XX-3866/UserDiscovery' into 'restructure'

Makefile

api/auth.go

bindings/ud.go

cmix/message/fingerprints.go

e2e/ratchet/partner/utils.go

go.mod

go.sum

single/cypher.go

single/interfaces.go

single/listener.go

single/message/collator.go

single/message/collator_test.go

single/message/request.go

single/message/requestPart.go

single/message/requestPart_test.go

single/receivedRequest.go

single/request.go

single/requestPartProcessor.go

single/responseProcessor.go

single/roundCollector.go