XD-2315 UI: Add support for stoppable notifications

* Update `angular-growl` to `angular-growl-2`
* Ensure Growl messages are shown nicely on small devices as well
XD-2323 Fix Batch replyChannel Header

JIRA: https://jira.spring.io/browse/XD-2323

Spring Integration 4.1.0 incorrectly mapped the `replyChannel`
header as a String, preventing the replacement with
the `xdReplyChannel` (transmitted as a String to the slave).

See INT-3555.

Set `overwrite="true"`.
XD-2296 Configure enable/disable message rate monitoring

 - Add new property `xd.messageRateMonitoring.enabled`
 - Gather message rates metrics only if this property is set to `true`
 - Set the client side property to `true` as we want this to be driven
from server side