[TASK] Drop LICENSE file in ext::t3editor

License file of codemirror is in the package itself.
Author information is available in git history.

Resolves: #68399
Releases: master
Change-Id: I8b5635de4761f4b3c90a7f3c8109f83a1ee3a515
Reviewed-on: http://review.typo3.org/41740


Reviewed-by: Frederic Gaus <frederic.gaus@flagbit.de>
Tested-by: Frederic Gaus <frederic.gaus@flagbit.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>