wip: TSS added to the gdt and start to implement scheduler

src/multitasking/scheduler.c

@@ -0,0 +1,11 @@
+#include "task.h"
+
+struct task *current_task;
+
+void scheduler(void)
+{
+	struct task *it = current_task->next;
+	while (it->status != RUN)
+		it = it->next;
+	switch_to_task(it);
+}