Core: Allow overriding the enabling of a code

If we want to enable codes in the default game INIs,
we should have some way for users to disable them.
This commit accomplishes that by adding a *_Disabled
section corresponding to each *_Enabled section.

Source/Core/Core/PatchEngine.h

@@ -33,7 +33,7 @@ struct Patch
 {
   std::string name;
   std::vector<PatchEntry> entries;
-  bool active = false;
+  bool enabled = false;
   bool user_defined = false;  // False if this code is shipped with Dolphin.
 };