Introduce @cocobot with a new trigger when mentioned, enhancing user interaction. Updated the introduction message in `/assets/cocobot-introduction.md` to dynamically include user mentions and version details. Transitioned license to CC BY 4.0, reflecting in `LICENSE`. Updated `CHANGELOG`, `CONTRIBUTING`, and `README.md` for clarity and consistency.

The bot now proudly announces its version 1.2.4, leaving the coconut jokes to its less useful counterpart, @ai. Feel free to contribute to its evolution on GitLab!

Signed-off-by: Kolja Nolte <kolja.nolte@gmail.com>