Comments system - Githubissues

Already started here: https://github.com/assemblee-virtuelle/welcometomyplace/pull/14

On the events page, replace the "Send message to organizer" block with a "Comments" block.

Comments are one level only at the moment. You cannot reply to another comment.

Add comment

At the top, display a text input to post a new comment

Allow to mention participants by name with a @. Mentionned participants should be added to the to property of the ActivityPub message being sent, so that they get the message and are notified
Allow to tag @invitees (if you are the organizer or an inviter) and @attendees (if you are an invitee). The to should then include the collection (/data/events/EVENT_ID/invitees or /data/events/EVENT_ID/attendees).
- The ActivityPub service should improved to take into account these collections, like it already does for the /followers collection. We should ensure only allowed users can send message to these collections.
All comments with the event ID in the context property should be added to a /comments collection associated with the event

Load the /comments collection associated with the event
Display the comments by date, with the user (picture, name), the text, the date.