Kernel: Add basic concept of Processes

We now create Shell as a process that has its own threads

kernel/include/kernel/Scheduler.h

@@ -21,11 +21,11 @@ namespace Kernel
 		void set_current_thread_sleeping(uint64_t);
 		[[noreturn]] void set_current_thread_done();
 
+		BAN::RefPtr<Thread> current_thread();
+
 	private:
 		Scheduler() = default;
 
-		BAN::RefPtr<Thread> current_thread();
-
 		void wake_threads();
 		[[nodiscard]] bool save_current_thread();
 		void remove_and_advance_current_thread();