CI: Switch drupalci image registry from dockerhub to gitlab.com (mitigate rate limit errors)
Problem/Motivation
Docker hub has significantly reduced rate limits for pulls as of 4/1, and also made unexpected changes to DA's dockerhub license.
Drupal CI is erroring due to limit - additional context + discussion in Drupal slack thread: https://drupal.slack.com/archives/CGKLP028K/p1743611728165519?thread_ts=1743001107.585039&cid=CGKLP028K
Steps to reproduce
Community is reporting CI failures
Proposed resolution
We are moving CI images off of docker hub to gitlab.com registy here: https://gitlab.com/drupal-infrastructure/drupalci/drupalci-environments/container_registry/
Remaining tasks
gitlab templates CI needs to be updated to point at new registry. I will open an MR.
Related issue: Issue #3516954
Related issue: Issue #3516973
Edited by drupalbot