Customizable script to allow honor from creature kills

* See CONF section: CUSTOM SERVER OPTIONS - CREATURE HONOR
* For existing servers, please import: characters_create_creaturehonor_message.sql
* Made a change to CMakeLists.txt which allows inclusion of custom scripts. Re-run CMake if you're not starting fresh.
Ignore the error if trying to insert a record for a GUID that already exists (duplicate key).