Refactor pets

* When summoning a pet the server will pick the best focus item you have equipped for that pets level range
 * Supports PoP and Luclin Focus items that work for NEC, MAG, BST
 * Focus Items are semi hard coded in a constant array so they are easy to add / update
 * spell_effect file is cleaned up
 * Pet scaling should work more like it did on Al'kabor
And necro pets are unneeded since necros dont have element specific focus items