Switch game settings to use a pointer

In order to add full per-game settings, we need to be able to tell yuzu to switch
to using either the global or game configuration. Using a pointer makes it easier
to switch.

src/core/hle/kernel/process.cpp

@@ -123,7 +123,7 @@ std::shared_ptr<Process> Process::Create(Core::System& system, std::string name,
                                                               : kernel.CreateNewUserProcessID();
     process->capabilities.InitializeForMetadatalessProcess();
 
-    std::mt19937 rng(Settings::values.rng_seed.value_or(0));
+    std::mt19937 rng(Settings::values->rng_seed.value_or(0));
     std::uniform_int_distribution<u64> distribution;
     std::generate(process->random_entropy.begin(), process->random_entropy.end(),
                   [&] { return distribution(rng); });