[Federation] isActorAbleToBeFollower stops Friendica instances from following

[gudzpoz]

The current implementation requires the following server actor to have an id ending in /relay:

Activity-Relay/api/resolver.go

Lines 185 to 188 in 7f942e7

	func isActorAbleToBeFollower(actorID *url.URL) bool {
	endingWithRelay := regexp.MustCompile(`/relay$`)
	return endingWithRelay.MatchString(actorID.Path)
	}

However, Friendica allows setting different actor names for the server actor, thus making it impossible for instances with a "wrong" server actor name to connect to Activity-Relay (using LitePub relay style).

I cannot find any documentation or speficication on ActivityPub relays, is it really necessary that actors be named relay?