CharDB Schema/Cleanup: cleanup channels table:

* rename columns (remove m_ prefix and convert to lowerCamel case);
* rename prepared statements to conform to standards (there is no CLEAN statement).

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

@@ -202,7 +202,8 @@ enum CharacterDatabaseStatements
     CHAR_ADD_CHANNEL,
     CHAR_SET_CHANNEL,
     CHAR_SET_CHANNEL_USAGE,
-    CHAR_CLEAN_CHANNEL,
+    CHAR_SET_CHANNEL_OWNERSHIP,
+    CHAR_DEL_OLD_CHANNELS,
 
     CHAR_SET_EQUIP_SET,
     CHAR_ADD_EQUIP_SET,