Apple M1 Support for MacOS

This commit adds support for compiling Dolphin for ARM on MacOS so that it can
run natively on the M1 processors without running through Rosseta2 emulation
providing a 30-50% performance speedup and less hitches from Rosseta2.

It consists of several key changes:

- Adding support for W^X allocation(MAP_JIT) for the ARM JIT
- Adding the machine context and config info to identify the M1 processor
- Additions to the build system and docs to support building universal binaries
- Adding code signing entitlements to access the MAP_JIT functionality
- Updating the MoltenVK libvulkan.dylib to a newer version with M1 support

Source/Core/Common/Arm64Emitter.cpp

@@ -21,6 +21,9 @@
 #ifdef _WIN32
 #include <Windows.h>
 #endif
+#ifdef __APPLE__
+#include <libkern/OSCacheControl.h>
+#endif
 
 namespace Arm64Gen
 {
@@ -342,7 +345,7 @@ void ARM64XEmitter::FlushIcacheSection(u8* start, u8* end)
   if (start == end)
     return;
 
-#if defined(IOS)
+#if defined(IOS) ||defined(__APPLE__)
   // Header file says this is equivalent to: sys_icache_invalidate(start, end - start);
   sys_cache_control(kCacheFunctionPrepareForExecution, start, end - start);
 #elif defined(WIN32)