Move ComputeTest,GraphicsTest,RenderTest and Std140Debug to the tests folder

Also renamed NazaraUnitTests to UnitTests

tests/Std140Debug/xmake.lua

@@ -0,0 +1,8 @@
+target("Std140Debug")
+	add_files("main.cpp")
+
+	if has_config("embed_rendererbackends") then
+		add_deps("NazaraRenderer")
+	else
+		add_deps("NazaraOpenGLRenderer")
+	end