[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/vfs/vfs_dump.cc

@@ -13,6 +13,7 @@
 
 #include "xenia/base/console_app_main.h"
 #include "xenia/base/cvar.h"
+#include "xenia/base/literals.h"
 #include "xenia/base/logging.h"
 #include "xenia/base/math.h"
 
@@ -22,6 +23,8 @@
 namespace xe {
 namespace vfs {
 
+using namespace xe::literals;
+
 DEFINE_transient_path(source, "", "Specifies the file to dump from.",
                       "General");
 
@@ -91,7 +94,7 @@ int vfs_dump_main(const std::vector<std::string>& args) {
         }
 
         // Allocate a buffer rounded up to the nearest 512MB.
-        buffer_size = xe::round_up(entry->size(), 512 * 1024 * 1024);
+        buffer_size = xe::round_up(entry->size(), 512_MiB);
         buffer = new uint8_t[buffer_size];
       }