[Base] Add user-literals for several memory sizes

Rather than using `n * 1024 * 1024`, this adds a convenient `_MiB`/`_KiB` user-literal to the new `literals.h` header to concisely describe units of memory in a much more readable way. Any other useful literals can be added to this header. These literals exist in the `xe::literals` namespace so they are opt-in, similar to `std::chrono` literals, and require a `using namespace xe::literals` statement to utilize it within the current scope.

I've done a pass through the codebase to replace trivial instances of `1024 * 1024 * ...` expressions being used but avoided anything that added additional casting complexity from `size_t` to `uint32_t` and such to keep this commit concise.

src/xenia/cpu/processor.cc

@@ -16,6 +16,7 @@
 #include "xenia/base/cvar.h"
 #include "xenia/base/debugging.h"
 #include "xenia/base/exception_handler.h"
+#include "xenia/base/literals.h"
 #include "xenia/base/logging.h"
 #include "xenia/base/memory.h"
 #include "xenia/base/profiling.h"
@@ -57,6 +58,8 @@ namespace cpu {
 using xe::cpu::ppc::PPCOpcode;
 using xe::kernel::XThread;
 
+using namespace xe::literals;
+
 class BuiltinModule : public Module {
  public:
   explicit BuiltinModule(Processor* processor)
@@ -142,8 +145,8 @@ bool Processor::Setup(std::unique_ptr<backend::Backend> backend) {
   // Open the trace data path, if requested.
   functions_trace_path_ = cvars::trace_function_data_path;
   if (!functions_trace_path_.empty()) {
-    functions_trace_file_ = ChunkedMappedMemoryWriter::Open(
-        functions_trace_path_, 32 * 1024 * 1024, true);
+    functions_trace_file_ =
+        ChunkedMappedMemoryWriter::Open(functions_trace_path_, 32_MiB, true);
   }
 
   return true;