Jala Offering for Shrines

The code for the Jala school offering for spellpower shrines already
existed, there was simply no item fulfilling the role.

Added a 'mystic perfume' shrine offering as a play on the 'vial of perfume' quest item that player lore always held as being the 'non functioning' Jala offering.

This item should now naturally occur in the Thrashers chest, which generates random offerings. Admins can also create it for quest rewards. There is, however, no chant for this item, as there are no priests of Jala.