Patched everything for aarch64, aside from scheduler, add more linker

points to aarch64 ld, add aarch64 heap, init, page tables and usermode,
make hhdm_offset a global atomic, aarch64 uses semihosting for output,
add generic PageTable type, add a function that creates and maps pages,
use allow to remove warnings, add a bufwriter so kernel panic always
works

GNUmakefile

@@ -54,6 +54,7 @@ run-aarch64: edk2-ovmf $(IMAGE_NAME).iso
 		-serial stdio \
 		-drive if=pflash,unit=0,format=raw,file=edk2-ovmf/ovmf-code-$(KARCH).fd,readonly=on \
 		-cdrom $(IMAGE_NAME).iso \
+		-semihosting-config enable=on,target=native \
 		$(QEMUFLAGS)
 
 .PHONY: run-hdd-aarch64