[Task] Markdown Examples under textarea

* CSS file Created
* JavaScript for Toogle Created
* Examples from typo3wiki on Forge moved to edit.html template

Change-Id: I057c64b4814663ad7686c1656e71efbfd64cbfe8
Resolves: #54150
Refs: #41966
Reviewed-on: https://review.typo3.org/25892
Reviewed-by: Bastian Bringenberg
Tested-by: Bastian Bringenberg