LS_COLORS support for other file attributes

[yunzheng]

Currently only symlinks, directories and regular files are colored when using ls in target-shell.

But other file attributes are currently not handled, such as setuid (u+s) and setgid (g+s) binaries, which are typically rendered with a red background in the default LS_COLORS configuration on Linux.

For a complete list of supported attributes, see the output of dircolors --print-database on Linux.