[3056] Allow Ghost Saber chanced spawn

See http://www.wowwiki.com/Cat_Figurine for details
Thanks to @X-Savior for providing the data
[3057] Fix some Ulduar issues and implement achievements 2996 and 2997

Signed-off-by: Xfurry <xfurry@scriptdev2.com>
[3058] Revert [3056]. It can be handled by DB

Thanks to @Neatelves
[3059] Update script for General Vezax

Thanks to @Ulduar for pointing the issues