remove unused types "starred" and "in-creation"

both are not used in productive:
- chat-id "in-creation" was dropped completely already in core-c
  as it does not allow assigning messages to chats in time.
- message flag "starred" was added at some point and never used.
  ux-wise, "disappearing messages" promises to clean up a chat -
  this does not fit well with "starring" messages.
  "saved messages" chat seems to be superior in that regard.
  but anyway, it is not used but comes at maintainance costs,
  so it is better to delete its functionality for now.
  (the db entries, however, are left for now,
  that might be more tricky to remove)

examples/repl/cmdline.rs

@@ -185,7 +185,7 @@ async fn log_msg(context: &Context, prefix: impl AsRef<str>, msg: &Message) {
     let temp2 = dc_timestamp_to_str(msg.get_timestamp());
     let msgtext = msg.get_text();
     println!(
-        "{}{}{}{}: {} (Contact#{}): {} {}{}{}{}{}{} [{}]",
+        "{}{}{}{}: {} (Contact#{}): {} {}{}{}{}{} [{}]",
         prefix.as_ref(),
         msg.get_id(),
         if msg.get_showpadlock() { "🔒" } else { "" },
@@ -193,7 +193,6 @@ async fn log_msg(context: &Context, prefix: impl AsRef<str>, msg: &Message) {
         &contact_name,
         contact_id,
         msgtext.unwrap_or_default(),
-        if msg.is_starred() { "★" } else { "" },
         if msg.get_from_id() == 1 as libc::c_uint {
             ""
         } else if msg.get_state() == MessageState::InSeen {
@@ -387,8 +386,6 @@ pub async fn cmdline(context: Context, line: &str, chat_id: &mut ChatId) -> Resu
                  listfresh\n\
                  forward <msg-id> <chat-id>\n\
                  markseen <msg-id>\n\
-                 star <msg-id>\n\
-                 unstar <msg-id>\n\
                  delmsg <msg-id>\n\
                  ===========================Contact commands==\n\
                  listcontacts [<query>]\n\
@@ -948,12 +945,6 @@ pub async fn cmdline(context: Context, line: &str, chat_id: &mut ChatId) -> Resu
             msg_ids[0] = MsgId::new(arg1.parse()?);
             message::markseen_msgs(&context, msg_ids).await;
         }
-        "star" | "unstar" => {
-            ensure!(!arg1.is_empty(), "Argument <msg-id> missing.");
-            let mut msg_ids = vec![MsgId::new(0); 1];
-            msg_ids[0] = MsgId::new(arg1.parse()?);
-            message::star_msgs(&context, msg_ids, arg0 == "star").await;
-        }
         "delmsg" => {
             ensure!(!arg1.is_empty(), "Argument <msg-id> missing.");
             let mut ids = [MsgId::new(0); 1];