Core/Calendar: Completely rewrite and fix most of the calendar system

There are still some issues that need to be fixed, for more info see CalendarHandler.cpp TODO part.
Some unblizzlike behaviour possible, we don't have a lot of sniffs.
Big thanks to @Warpten, he joined my project and helped a lot.

IMPORTANT NOTE: Read / append packed time functions in ByteBuffer.h are not correct, they need to be fixed in order to have event times accurate

Signed-off-by: Nay <dnpd.dd@gmail.com>

src/server/shared/Database/Implementation/CharacterDatabase.cpp

@@ -535,4 +535,10 @@ void CharacterDatabaseConnection::DoPrepareStatements()
     PREPARE_STATEMENT(CHAR_INS_CHAR_TALENT, "INSERT INTO character_talent (guid, spell, spec) VALUES (?, ?, ?)", CONNECTION_ASYNC);
     PREPARE_STATEMENT(CHAR_DEL_CHAR_ACTION_EXCEPT_SPEC, "DELETE FROM character_action WHERE spec<>? AND guid = ?", CONNECTION_ASYNC);
     PREPARE_STATEMENT(CHAR_SEL_CHAR_PET_BY_ENTRY_AND_SLOT, "SELECT id, entry, owner, modelid, level, exp, Reactstate, slot, name, renamed, curhealth, curmana, curhappiness, abdata, savetime, CreatedBySpell, PetType FROM character_pet WHERE owner = ? AND slot = ?", CONNECTION_SYNCH);
+
+    // Calendar
+    PREPARE_STATEMENT(CHAR_REP_CALENDAR_EVENT, "REPLACE INTO calendar_events (id, creator, title, description, type, dungeon, eventtime, flags, time2) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)", CONNECTION_ASYNC);
+    PREPARE_STATEMENT(CHAR_DEL_CALENDAR_EVENT, "DELETE FROM calendar_events WHERE id = ?", CONNECTION_ASYNC);
+    PREPARE_STATEMENT(CHAR_REP_CALENDAR_INVITE, "REPLACE INTO calendar_invites (id, event, invitee, sender, status, statustime, rank, text) VALUES (?, ?, ?, ?, ?, ?, ?, ?)", CONNECTION_ASYNC);
+    PREPARE_STATEMENT(CHAR_DEL_CALENDAR_INVITE, "DELETE FROM calendar_invites WHERE id = ?", CONNECTION_ASYNC);
 }