feat: 添加对内核引导协议的抽象 (#913)

* 添加multiboot header

* head.S传参增加bootloader类型

* feat: 添加引导加载协议的抽象,并为multiboot2实现这个抽象.

* 把framebuffer的映射地址改为从early ioremap和mmio pool分配

* riscv64能运行

.vscode/settings.json

@@ -129,7 +129,6 @@
         "assert.h": "c",
         "sys_version.h": "c",
         "cmd.h": "c",
-        "sleep.h": "c",
         "net.h": "c",
         "cmd_test.h": "c",
         "cmpxchg.h": "c",