Bring back global lithium pools

why?
cause sorting around the global driver pool would basically use more cpu power then just copy data sequences into the right order
And sorting data references costs 0 performance at all

include/pd/lithium/pools.hpp

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <pd/core/core.hpp>
+#include <pd/lithium/vertex.hpp>
+
+namespace PD {
+namespace Li {
+PD_API PD::Pool<Vertex>& GetVertexPool();
+PD_API PD::Pool<u16>& GetIndexPool();
+PD_API void ResetPools();
+}  // namespace Li
+}  // namespace PD