[TASK] Implement t3editor as custom web component

Remove jQuery dependency, avoid inline javascript and
encapsulate initialization into a web component.

Also use "codemirror" as import name, as that's
what the npm package name is, and will eventually
allow to make use of TypeScript typings.

Releases: master
Resolves: #93149
Change-Id: Ia85784b21a90e1986ea6ba7a915e032aa7963d92
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/67185


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>