Add tar.gz/tar.bz2/tar.xz support, simple validation, use mktemp:

- Add tar.gz, tar.bz2, tar.xz support
- Simple validate check if archive file follows right directory
  structure (i.e. it contains "bin")
- Download files under temporary dir created by mktemp instead of
  using /tmp/nixstall-archive.zip to avoid file conflict.