[client,management] Feature/client service expose (#5411)

CLI: new expose command to publish a local port with flags for PIN, password, user groups, custom domain, name prefix and protocol (HTTP default).
Management/API: create/renew/stop expose sessions (streamed status), automatic naming/domain, TTL renewals, background expiration, new management RPCs and client methods.
UI/API: account settings now include peer_expose_enabled and peer_expose_groups; new activity codes for peer expose events.

management/internals/server/boot.go

@@ -152,6 +152,8 @@ func (s *BaseServer) GRPCServer() *grpc.Server {
 		if err != nil {
 			log.Fatalf("failed to create management server: %v", err)
 		}
+		srv.SetReverseProxyManager(s.ReverseProxyManager())
+		srv.StartExposeReaper(context.Background())
 		mgmtProto.RegisterManagementServiceServer(gRPCAPIHandler, srv)
 
 		mgmtProto.RegisterProxyServiceServer(gRPCAPIHandler, s.ReverseProxyGRPCServer())