kernel: Make the address arbiter instance per-process

Now that we have the address arbiter extracted to its own class, we can
fix an innaccuracy with the kernel. Said inaccuracy being that there
isn't only one address arbiter. Each process instance contains its own
AddressArbiter instance in the actual kernel.

This fixes that and gets rid of another long-standing issue that could
arise when attempting to create more than one process.

src/core/core.cpp

@@ -116,7 +116,7 @@ struct System::Impl {
         if (web_browser == nullptr)
             web_browser = std::make_unique<Core::Frontend::DefaultWebBrowserApplet>();
 
-        auto main_process = Kernel::Process::Create(kernel, "main");
+        auto main_process = Kernel::Process::Create(system, "main");
         kernel.MakeCurrentProcess(main_process.get());
 
         telemetry_session = std::make_unique<Core::TelemetrySession>();