Cleanup non-rest apiserver handlers

- rename MuxHelper -> PathRecorderMux
- move non-rest handlers into routes packages within genericapiserver and
  `pkg/routes` (those from master)
- move ui and logs handlers out of genericapiserver (they are
  not generic)
- make version handler configurable (`config.EnableVersion`)

test/integration/openshift/openshift_test.go

@@ -28,11 +28,12 @@ import (
 func TestMasterExportsSymbols(t *testing.T) {
 	_ = &master.Config{
 		Config: &genericapiserver.Config{
-			EnableUISupport:      false,
 			EnableSwaggerSupport: false,
 			RestfulContainer:     nil,
 		},
 		EnableCoreControllers: false,
+		EnableUISupport:       false,
+		EnableLogsSupport:     false,
 	}
 	m := &master.Master{
 		GenericAPIServer: &genericapiserver.GenericAPIServer{},