add materials for windows and linux install

source/Installation/linux.rst

source/Installation/windows.rst

source/_static/install/linux_boot_key.jpg

source/_static/install/linux_create_main_user.jpg

source/_static/install/linux_install_dual_boot.jpg

source/_static/install/linux_install_xubuntu.jpg

source/_static/install/linux_select_install_mode.jpg

source/_static/install/linux_select_keyboard.jpg

source/_static/install/linux_select_lang.jpg

source/_static/install/windows_boot_key.jpg

source/_static/install/windows_custom_install.jpg

source/_static/install/windows_install.jpg

source/_static/install/windows_license.jpg

source/_static/install/windows_new_partition.jpg

source/_static/install/windows_rearange_partition.jpg

source/_static/install/windows_select_lang.jpg