Separate out a base MessageContentModel.

Separate out a base `MessageContentModel` that can be extended to get the component types from different places. This is used currently for `EventMessageContentModel` but will be used later as part of the rich chat bar.

All display text is now in the text component so it never needs special casing. This also cleans up some of the model parameters so more things come from attributes including location and file data (which was already a qvariantmap anyway).

Also cleaned up the itinerary and file enhancement views,

src/libneochat/eventhandler.cpp

@@ -198,6 +198,10 @@ bool EventHandler::isHidden(const NeoChatRoom *room, const Quotient::RoomEvent *
 
 Qt::TextFormat EventHandler::messageBodyInputFormat(const Quotient::RoomMessageEvent &event)
 {
+    if (event.isRedacted() && !event.isStateEvent()) {
+        return Qt::RichText;
+    }
+
     if (event.mimeType().name() == "text/plain"_L1) {
         return Qt::PlainText;
     } else {
@@ -207,6 +211,11 @@ Qt::TextFormat EventHandler::messageBodyInputFormat(const Quotient::RoomMessageE
 
 QString EventHandler::rawMessageBody(const Quotient::RoomMessageEvent &event)
 {
+    if (event.isRedacted() && !event.isStateEvent()) {
+        auto reason = event.redactedBecause()->reason();
+        return (reason.isEmpty()) ? i18n("<i>[This message was deleted]</i>") : i18n("<i>[This message was deleted: %1]</i>", reason.toHtmlEscaped());
+    }
+
     QString body;
 
     if (event.has<EventContent::FileContent>()) {