Added sequence to remap PIC

Wrote GDT code in C
Added routines to initialize GDT and IDT

src/x86/isr.h

@@ -1,5 +1,8 @@
 #pragma once
 
+__attribute__ ((interrupt))
+void isr_generic(void* frame);
+
 __attribute__ ((interrupt))
 void isr_division_by_zero(void* frame);