1. change some directory structure for the build script

2. add build script and document
   see DOC/BuildVentoyFromSource.txt for detail

GRUB2/README.txt

-
-========== About Source Code =============
-Ventoy use grub-2.04, so I only put the added and modified source code here.
-
-You can download grub-2.04 source code from this site:
-https://ftp.gnu.org/gnu/grub/
-
-Just merge the code here with the original code of grub-2.04
-
-
-========== Build =============
-./autogen.sh
-./configure 
-make

GRUB2/buildgrub.sh

+#!/bin/bash
+
+VT_GRUB_DIR=$PWD
+
+rm -rf INSTALL
+rm -rf SRC
+rm -rf NBP
+rm -rf PXE
+
+mkdir SRC
+mkdir NBP
+mkdir PXE
+
+tar -xvf grub-2.04.tar.xz -C ./SRC/
+
+/bin/cp -a ./MOD_SRC/grub-2.04  ./SRC/
+
+cd ./SRC/grub-2.04
+
+# build for Legacy BIOS 
+./autogen.sh
+./configure  --prefix=$VT_GRUB_DIR/INSTALL/
+make -j 16
+sh install.sh
+
+# build for UEFI
+make distclean
+./autogen.sh
+./configure  --with-platform=efi --prefix=$VT_GRUB_DIR/INSTALL/
+make -j 16
+sh install.sh  uefi
+
+
+cd ../../
+

IPXE/README.txt

-
-========== About Source Code =============
-1. unpack ipxe_org_code/ipxe-3fe683e.tar.bz2
-2. After decompressing, delete ipxe-3fe683e/src/drivers (whole directory)
-3. Merge left source code with the ipxe-3fe683e directory here
-
-========== Build =============
-make bin/ipxe.iso