This is a new collator type that follows proposal 220 for deciding
which identities to include. The rule is (approximately):
If a <ed,rsa> identity is listed by more than half of authorities,
include it. And include all <rsa> votes about that node as
matching.
Otherwise, if an <*,rsa> or <rsa> identity is listed by more than
half of the authorities, and no <ed,rsa> has been listed, include
it.