setup.py has invalid url as "url" attribute

[Moshe Zadka]

In setup.py the URL is https://github.com/teradatalabs/presto-admin instead of https://github.com/prestodb/presto-admin

This link gets into PyPI and makes it hard to find the source (luckily the README has the right URL).

[Akshat Nair]

We should replace it with https://github.com/Teradata/presto-admin