Add KeepQuotedReply option for matrix to fix regression (#1823)

Matrix quotes replies and as of matterbridge 1.24.0 we strip those as this causes
issues with bridges support threading and have PreserveThreading enabled.

Introduced via 9a8ce9b17e

But if you for example use mattermost or discord with webhooks you'll need to enable
this if you want something that looks like a reply from matrix.
See issues:
- https://github.com/42wim/matterbridge/issues/1819
- https://github.com/42wim/matterbridge/issues/1780

bridge/matrix/matrix.go

@@ -428,12 +428,15 @@ func (b *Bmatrix) handleReply(ev *matrix.Event, rmsg config.Message) bool {
 	}
 
 	body := rmsg.Text
-	for strings.HasPrefix(body, "> ") {
-		lineIdx := strings.IndexRune(body, '\n')
-		if lineIdx == -1 {
-			body = ""
-		} else {
-			body = body[(lineIdx + 1):]
+
+	if !b.GetBool("keepquotedreply") {
+		for strings.HasPrefix(body, "> ") {
+			lineIdx := strings.IndexRune(body, '\n')
+			if lineIdx == -1 {
+				body = ""
+			} else {
+				body = body[(lineIdx + 1):]
+			}
 		}
 	}