Add base and beam attributes for ender_crystal NPC type

[AfkF24]

Would allow for further customization by being able show/hide the end crystal base, as well as having the beam target set. A workaround for having the beam appear right now is spawning an ender dragon NPC in close proximity of the ender crystal, which automatically shoots the beam at the dragon. Only really useful if you want to point the beam underground, since you probably wouldn't want a random ender dragon floating in the air lmao