core/memory: Introduce skeleton of Memory class

Currently, the main memory management code is one of the remaining
places where we have global state. The next series of changes will aim
to rectify this.

This change simply introduces the main skeleton of the class that will
contain all the necessary state.

src/core/memory.h

@@ -8,6 +8,10 @@
 #include <string>
 #include "common/common_types.h"
 
+namespace Core {
+class System;
+}
+
 namespace Kernel {
 class Process;
 }
@@ -36,6 +40,23 @@ enum : VAddr {
     KERNEL_REGION_END = KERNEL_REGION_VADDR + KERNEL_REGION_SIZE,
 };
 
+/// Central class that handles all memory operations and state.
+class Memory {
+public:
+    explicit Memory(Core::System& system);
+    ~Memory();
+
+    Memory(const Memory&) = delete;
+    Memory& operator=(const Memory&) = delete;
+
+    Memory(Memory&&) = default;
+    Memory& operator=(Memory&&) = default;
+
+private:
+    struct Impl;
+    std::unique_ptr<Impl> impl;
+};
+
 /// Changes the currently active page table to that of
 /// the given process instance.
 void SetCurrentPageTable(Kernel::Process& process);