1. change some directory structure for the build script

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

EDK2/buildedk.sh

@@ -0,0 +1,33 @@
+#!/bin/sh
+
+rm -rf edk2-edk2-stable201911
+
+unzip edk2-edk2-stable201911.zip
+
+/bin/cp -a ./edk2_mod/edk2-edk2-stable201911  ./
+
+cd edk2-edk2-stable201911
+
+VTEFI_PATH=Build/MdeModule/RELEASE_GCC48/X64/MdeModulePkg/Application/Ventoy/Ventoy/OUTPUT/Ventoy.efi
+DST_PATH=../../INSTALL/ventoy/ventoy_x64.efi
+
+rm -f $VTEFI_PATH
+rm -f $DST_PATH
+
+make -j 4 -C BaseTools/
+
+source ./edksetup.sh
+build -p MdeModulePkg/MdeModulePkg.dsc -a X64 -b RELEASE -t GCC48
+
+if [ -e $VTEFI_PATH ]; then
+    echo -e '\n\n====================== SUCCESS ========================\n\n'    
+    cp -a $VTEFI_PATH $DST_PATH
+    cd ..
+else
+    echo -e '\n\n====================== FAILED ========================\n\n'
+    cd ..
+    exit 1
+fi
+
+
+