One bus: the AMQP transport is gone from the controller

The mesh runs on the seat's bus alone (novox/hq ADR 0131, design 28 task 5.5). The old
transport's consume loop, build request, tool ask, management API and account scoping are
deleted, and the bus switch with them; the controller connects to the broker seat and to
nothing else. The store-window tests keep their assertions on a bus-less fake, and the tests
that only made sense for the old transport's in-memory holding go with it.

internal/link/enrolment.go

@@ -24,10 +24,9 @@ import (
 // — it holds both grants and asks each for its part, which is what the process running them is
 // for.
 type Enrolment struct {
-	Inventory  *inventory.Inventory
-	Identity   *identity.Identity
-	Management *broker.Management
-	Broker     broker.Broker
+	Inventory *inventory.Inventory
+	Identity  *identity.Identity
+	Broker    broker.Broker
 
 	// OnNATS says the mesh's own traffic is on the bus being built, so a node's credential is
 	// minted into the mesh's records and composed into the bus's user list rather than pushed
@@ -194,17 +193,6 @@ func (e Enrolment) Enrol(ctx context.Context, request EnrolRequest) (reply Enrol
 			reply.Password = password
 		}
 
-	case e.Management != nil:
-		password, err := freshPassword()
-		if err != nil {
-			return EnrolReply{}, err
-		}
-		if err := e.Management.CreateNodeAccount(ctx, node.Name, password); err != nil {
-			log.Printf("%s is enrolled and its broker password could not be replaced, so it keeps "+
-				"the token's secret as its password: %v", node.Name, err)
-		} else {
-			reply.Password = password
-		}
 	}
 
 	if profile != nil {
@@ -261,9 +249,6 @@ func freshPassword() (string, error) {
 
 var _ Enroller = Enrolment{}
 
-// ErrNoBrokerManagement is returned when an account cannot be made because nothing was configured.
-var ErrNoBrokerManagement = errors.New("no broker management configured")
-
 // Heard records what a node reported about itself.
 //
 // A node states; the owning context writes (novox/hq ADR 0006). What a node says it applied is