Improve GraphQL documentation and cleanup API

Signed-off-by: Thomas Citharel <tcit@tcit.fr>

js/src/graphql/comment.ts

@@ -68,18 +68,8 @@ export const COMMENTS_THREADS = gql`
 `;
 
 export const CREATE_COMMENT_FROM_EVENT = gql`
-  mutation CreateCommentFromEvent(
-    $eventId: ID!
-    $actorId: ID!
-    $text: String!
-    $inReplyToCommentId: ID
-  ) {
-    createComment(
-      eventId: $eventId
-      actorId: $actorId
-      text: $text
-      inReplyToCommentId: $inReplyToCommentId
-    ) {
+  mutation CreateCommentFromEvent($eventId: ID!, $text: String!, $inReplyToCommentId: ID) {
+    createComment(eventId: $eventId, text: $text, inReplyToCommentId: $inReplyToCommentId) {
       ...CommentRecursive
     }
   }