[z2124] Add new table `creature_template_spells` to store a creature's spells

This will replace old creature_template.spell1-4 fields. Note: Removing them from the database will come soon

Signed-off-by: Schmoozerd <schmoozerd@cmangos>

(based on commit [12189] - 82199ec)

(based on commit [s1750] - 11fcb4c)