Implemented guest-to-host function pointers (#7)

* Implemented guest-to-host function pointers (WIP)

Co-Authored-By: Skyth (Asilkan) <19259897+blueskythlikesclouds@users.noreply.github.com>

* function: support more types for function pointers

* api: ported BlueBlur headers and misc. research

* Move over function-pointers changes from options-menu branch.

---------

Co-authored-by: Skyth (Asilkan) <19259897+blueskythlikesclouds@users.noreply.github.com>

UnleashedRecomp/api/CSD/Manager/csdmObserverBase.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include "SWA.inl"
+
+namespace Chao::CSD
+{
+    template<typename TObservee>
+    class CObserverBase
+    {
+    public:
+        struct Vftable
+        {
+            be<uint32_t> m_fpDtor;
+        };
+
+        xpointer<Vftable> m_pVftable;
+        SWA_INSERT_PADDING(0x08);
+
+        ~CObserverBase();
+    };
+}
+
+#include "CSD/Manager/csdmObserverBase.inl"