[FEATURE] Introduce JavaScript Notification API

This patch introduces the new JavaScript Notification API and removes
the refactoring of the FlashMessage API which was made for TYPO3 CMS 7.0

The compatibility layer for TYPO3.FlashMessage has changed to use
the new Notification API and will be removed with TYPO3 CMS 9.

Resolves: #66047
Releses: master
Change-Id: I025fea5ba735bec42658420917e73daa54d97553
Reviewed-on: http://review.typo3.org/38270


Reviewed-by: Benjamin Kott <info@bk2k.info>
Tested-by: Benjamin Kott <info@bk2k.info>
Reviewed-by: Jan Helke <typo3@helke.de>
Tested-by: Jan Helke <typo3@helke.de>
Reviewed-by: Benjamin Mack <benni@typo3.org>
Tested-by: Benjamin Mack <benni@typo3.org>