Introduced simple task

Loaders are not suitable for one shot tasks which execution needs to be guaranteed

app/src/main/java/eu/faircode/email/DaoMessage.java

@@ -92,6 +92,9 @@ public interface DaoMessage {
             " WHERE message.id = :id")
     LiveData<TupleMessageEx> liveMessage(long id);
 
+    @Query("SELECT * FROM message WHERE msgid = :msgid")
+    LiveData<EntityMessage> liveMessageByMsgId(String msgid);
+
     @Query("SELECT uid FROM message WHERE folder = :folder AND received >= :received AND NOT uid IS NULL")
     List<Long> getUids(long folder, long received);