feat(loader, kernel): impl part of loader and initialize kernel structure

tools/run_qemu.sh

@@ -0,0 +1,7 @@
+#!/usr/bin/env bash
+qemu-system-x86_64 \
+    -enable-kvm -cpu host \
+    -drive file=zig-out/disk.img,format=raw \
+    -drive if=pflash,readonly=on,file=/usr/share/edk2/ovmf/OVMF_CODE.fd \
+    -serial stdio
+    # -s -S