feat(LuaEngine/Packet): Add support ReadPackedGUID

[mostlynick3]

Adds support for reading packed GUIDs in worldpackets (see e.g., packets SMSG_MOVE_GRAVITY_DISABLE, SMSG_MOVE_GRAVITY_ENABLE, SMSG_SPLINE_MOVE_START_SWIM, SMSG_SPLINE_MOVE_STOP_SWIM, SMSG_DESTRUCTIBLE_BUILDING_DAMAGE, and others that use PackGUID instead of a full GUID), and closes #194

Tested with PackedGUID implementation of example script of issue 194.

local function OnPacketSend(event, packet, player)
	if packet:GetOpcode() == 592 then -- Direct damage combat log
		local packetSize = packet:GetSize()
		print("Packet size: " .. tostring(packetSize))

		local TargetPackedGUID = packet:ReadPackedGUID()
		print("Target GUID Byte " .. tostring(TargetPackedGUID))

		local AttackerPackedGUID = packet:ReadPackedGUID()
		print("Attacker GUID Byte " .. tostring(AttackerPackedGUID))

		-- The following values are generally accurate
		-- Read spell ID (4 bytes)
		local spellId = packet:ReadULong()
		print("Spell ID: " .. spellId)

		-- Read damage value (4 bytes)
		local damage = packet:ReadULong()
		print("Damage: " .. damage)

		-- Read overkill value (4 bytes)
		local overkill = packet:ReadULong()
		print("Overkill: " .. overkill)

		-- Read damage type (1 byte)
		local schoolMask = packet:ReadUByte()
		print("School Mask: " .. schoolMask)

		-- Read absorbed damage value (4 bytes)
		local absorb = packet:ReadULong()
		print("Absorb: " .. absorb)

		-- Read resisted damage value (4 bytes)
		local resist = packet:ReadULong()
		print("Resist: " .. resist)

		-- Read physical log flag (1 byte)
		local physicalLog = packet:ReadUByte()
		print("Physical Log: " .. physicalLog)

		-- Read unused field (1 byte)
		local unused = packet:ReadUByte()
		print("Unused: " .. unused)

		-- Read blocked damage value (4 bytes)
		local blocked = packet:ReadULong()
		print("Blocked: " .. blocked)

		-- Read hit info (4 bytes)
		local hitInfo = packet:ReadULong()
		print("Hit Info: " .. hitInfo)

		-- Read hit info (duplicate) (4 bytes)
		local hitInfo2 = packet:ReadULong()
		print("Hit Info 2: " .. hitInfo2)

		-- Read extended data flag (1 byte)
		local hitInfo3 = packet:ReadUByte()
		print("Hit Info 3: " .. hitInfo3)
	end
end

RegisterServerEvent(7, OnPacketSend)