[/done] Thank automatically people mentioned on a done

[melalj]

If a task was done and includes a mention of another member, maybe we can give credits to the participating member as well as thanks.

For example: /done completed on-boarding on Mangrove ecosystem with @adrien

Maybe we can keep it as is, but need to input 2 commands /done and /thanks to give credits to the participating members

[tjeanneau]