[Testing] Re-Adding Destroy Missions

On Dantooine, all missions but my added 3 are commented out.  Also lowered the difficulty of those 3 to where I should be able to get (for testing) at TKM.  Corellia is functional.

Steps followed:
1) Create new mission template in npc_mission
2) Declare it in serverobjects.lua
3) Add it to the appropriate planet's destroy mission .lua file in /scripts/mobile/spawn/destroy_mission