Retire legacy domain names

[miketheman]

PyPI has a long history of domains, and is now only hosted at https://pypi.org

All other domain names should effectively be redirected, increasing overall latency, traffic handling, and incurs a non-zero maintenance overhead.

Configured here:
https://github.com/pypi/infra/blob/f286e031d8260b6b58ce610fb5875bc032285835/terraform/main.tf#L94
https://github.com/pypi/infra/blob/682d131c065961a93d7392071c03970ee86c58a4/terraform/warehouse/vcl/main.vcl#L273-L301

Explore retiring these older domains to remove this source of traffic.

Consider: schedule, brownouts, announcements, et al