Change DB stucture, improve LMC behaviour

**Please, backup your DB before performing any testing.**

Introduce new DB structure and DB migration mechanism.
Index `timestamp`, `to_jid`, `from_jid` columns to improve performance.
Add trigger for `replaced_by_db_id` calculation by DB on message insert.

Now LMC messages are interconnected with original messages,
this way we have fast access to last (hence correct) applicable edits,
as well as reference to the original message from any edit (in case of chained edits).

Change the way LMC messages are being displayed. Now we check if we
can replace a message from current buffer. If we don't have a message in
the buffer, it might've been lost, but we can still display it as a
new message.

Further information available here:
https://github.com/profanity-im/profanity/pull/1893
https://github.com/profanity-im/profanity/issues/1899
https://github.com/profanity-im/profanity/pull/1902

src/ui/chatwin.c

@@ -451,8 +451,8 @@ chatwin_outgoing_msg(ProfChatWin* chatwin, const char* const message, char* id,
         win_print_outgoing((ProfWin*)chatwin, enc_char, id, replace_id, message);
     }
 
-    // save last id and message for LMC
-    if (id) {
+    // save last id and message for LMC in case if it's not LMC message
+    if (id && !replace_id) {
         _chatwin_set_last_message(chatwin, id, message);
     }
 }