Download: Handle zip files (instead of tar.gz)

[codeswhite]

For example when downloading entry #2 from the default downloads list it gives an error:

Enter number > 2
[+] Downloading & ungzipping 'afrikaans/afr_dbf.zip'
Traceback (most recent call last):
  File "/home/maxon/.local/bin/stargen", line 8, in <module>
    sys.exit(main())
  File "/home/maxon/.local/lib/python3.9/site-packages/stargen/__main__.py", line 15, in main
    Stargen(parse_args())
  File "/home/maxon/.local/lib/python3.9/site-packages/stargen/stargen.py", line 97, in __init__
    menu.get(cmd)[0](args)
  File "/home/maxon/.local/lib/python3.9/site-packages/stargen/modules/download.py", line 273, in download
    gzip.decompress(web.read()))
  File "/usr/lib/python3.9/gzip.py", line 556, in decompress
    return f.read()
  File "/usr/lib/python3.9/gzip.py", line 300, in read
    return self._buffer.read(size)
  File "/usr/lib/python3.9/gzip.py", line 487, in read
    if not self._read_gzip_header():
  File "/usr/lib/python3.9/gzip.py", line 435, in _read_gzip_header
    raise BadGzipFile('Not a gzipped file (%r)' % magic)
gzip.BadGzipFile: Not a gzipped file (b'PK')