[TASK] Add a code of coduct document
Having a CODE_OF_CONDUCT.md document that links to the TYPO3 code of conduct provides users who view the project source on GitLab easy, direct access to the full text.
Having a CODE_OF_CONDUCT.md document that links to the TYPO3 code of conduct provides users who view the project source on GitLab easy, direct access to the full text.