distro_check: partial rewrite to make it work again

distro_check: partial rewrite to make it work again

This library suffered as part of the Python 2 to Python 3 migration and stopped
working entirely.

Fix all the migration problems such as files being treated as strings but opened
in binary mode, insufficient use of with on files, and so on.

Rewrite large amounts to be Pythonic instead of C-in-Python.

Update OpenSuse and Fedora URLs.

Fedora now splits the archive alphabetically so handle that.

[ YOCTO #10562 ]

Signed-off-by: Ross Burton <ross.burton@intel.com>