Related Conversation Widget needs UI Update

[westei]

The old Related Conversation (class: ConversationMLTQueryBuilder, creator: query_related_mlt used the assumption that the first message in a conversation is the question and follow up messages are answers. This assumption breaks down when Smarti is used with public channels. In such a setting one would like to search for relevant sections in conversations and the Widget should show the most relevant message plus nearby messages on user interaction.

While the server side implementation was already updates as part of #303 this will also require updates to the response format and the UI of the widget.

With the new version the message initially shown (as most relevant within the section) may no longer be the first so the old format of a question and multiple answers does no longer fit.

The suggestion would be to just return the messages of the section and mark the most relevant message within this section so that the Widget can present it to the user

[Peym4n]

As discussed with @westei the UI for conversation MLT results inherits the message context UI from conversation search, with the difference that the context messages won't be interactive and the main message will be posted as a link, when enough data (room ID and message ID) is available. In this case there is also a link in the results UI to jump to the message.