Previously all wizard items not of type credential were forced to be last,
but it suffices to force only items having no credential type to be last
(regardless of their type), because only those cannot be taken into account
in the dependency expansion algorithm.

The revocation subcommands are now subcommands of irma issuer.

Sietse Ringers authored Feb 26, 2021 and Ivar Derksen committed Feb 26, 2021

feat: improve warning and suppress stacktrace in IRMA server log in case /statusevents is hit while SSE is disabled

This makes it easier to implement stateless servers

feat: add flag to wizard (dis)allowing it to be started by requestors other than the owning requestor

feat: require AllowUnsignedCallbacks to be set for chained sessions if no JWT private key is configured

# Conflicts:
#	descriptions.go
#	internal/sessiontest/session_test.go
#	schemes.go