ShockAirHeads

Updated to use Packet based entities instead of actual armorstands. This introduces AirHeads which are only visible on the client & do not appear on the server.

• Implemented packet-based AirHead entities using PacketEvents.
• Fixed an issue with config sound names & also added ability to use custom sounds.
• Added the ability to place the hologram under or above the AirHead.
• Removed config option "run-clean-on-start", as we dont use entities anymore.