core/memory: Migrate over Write{8, 16, 32, 64, Block} to the Memory class

The Write functions are used slightly less than the Read functions,
which make these a bit nicer to move over.

The only adjustments we really need to make here are to Dynarmic's
exclusive monitor instance. We need to keep a reference to the currently
active memory instance to perform exclusive read/write operations.

src/core/memory/cheat_engine.cpp

@@ -30,7 +30,7 @@ void StandardVmCallbacks::MemoryRead(VAddr address, void* data, u64 size) {
 }
 
 void StandardVmCallbacks::MemoryWrite(VAddr address, const void* data, u64 size) {
-    WriteBlock(SanitizeAddress(address), data, size);
+    system.Memory().WriteBlock(SanitizeAddress(address), data, size);
 }
 
 u64 StandardVmCallbacks::HidKeysDown() {