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

arch/x86_64/io.zig

@@ -0,0 +1,19 @@
+pub fn outb(port: u16, value: u8) void {
+    asm volatile (
+        \\outb %al, %dx
+        :
+        : [port] "{dx}" (port), [value] "{al}" (value)
+        : .{}
+    );
+}
+
+pub fn inb(port: u16) u8 {
+    var value: u8 = 0;
+    asm volatile (
+        \\inb %dx, %al
+        : [value] "={al}" (value)
+        : [port] "{dx}" (port)
+        : .{}
+    );
+    return value;
+}