Rename SystemDriver to WindowDriver and removed LinuxSystemDriver

Hopefully the last time I change my mind on what I want these to be
called. Reason behind this change is to minimize scope of a single
module. The WindowDriver should really only handle stuff related to
windows. If we need OS level functionality (e.g. get_os_name), that
should be the responsibility of the OS driver (or whatever that ends
being called). Remember, composition over inheritance.

engine/src/drivers/x11/window_driver.h

@@ -0,0 +1,24 @@
+/**
+ * Copyright (c) 2025, Jayden Grubb <contact@jaydengrubb.com>
+ * 
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#pragma once
+
+#ifdef NOVA_X11
+
+#include <X11/Xlib.h>
+#include <nova/platform/window_driver.h>
+
+namespace Nova {
+	class X11WindowDriver final : public WindowDriver {
+	  public:
+		X11WindowDriver();
+		~X11WindowDriver() override;
+
+		[[nodiscard]] const char* get_surface_extension() const override;
+	};
+} // namespace Nova
+
+#endif // NOVA_X11