plugin: Migrate 'merge' utility into Dictionary module

plugin/src/Dictionary.lua

@@ -0,0 +1,33 @@
+--[[
+	This is a placeholder module waiting for Cryo to become available.
+]]
+
+local None = newproxy(true)
+getmetatable(None).__tostring = function()
+	return "None"
+end
+
+local function merge(...)
+	local output = {}
+
+	for i = 1, select("#", ...) do
+		local source = select(i, ...)
+
+		if source ~= nil then
+			for key, value in pairs(source) do
+				if value == None then
+					output[key] = nil
+				else
+					output[key] = value
+				end
+			end
+		end
+	end
+
+	return output
+end
+
+return {
+	None = None,
+	merge = merge,
+}