Obtain gnu software from ftpmirror.gnu.org

Summary

Pipelines sometimes fail because connection ftp.gnu.org times out.

This also happens locally.

I propose we use ftpmirror.gnu.org .

There's already an MR open to fix this issue here

Steps to reproduce

This cannot be reproduced, it is dependent on ftp.gnu.org .

Please see examples in parent epic.

What is the current bug behavior?

Connection to ftp.gnu.org times out when trying to download dependent software.

What is the expected correct behavior?

Timeouts should be a rare occurence.