Feature: #64726 - Added support for multiple FlashMessage queues

See Issue #64726

Description

In Extbase ControllerContext the method getFlashMessageQueue() now optionally allows to specify which queue to fetch. If none is specified the default- messagequeue for the current controller/plugin will be used.

$this->controllerContext->getFlashMessageQueue($queueIdentifier);

In Fluid the flashMessages-ViewHelper also allows to specify a queue to use.

<f:flashMessages queueIdentifier="myQueue" />

Impact

Extensions may now render foreign flash message queues and add messages to them.