Create boolean for determining base image registry

This template is ONLY used for quick fixes/adds (primarily for tracking smaller issues). New feature request, pipeline enhancement, and bug issues should use the other template options for issue submission.

Quick Fix / Add

We previously made an update to the build stage as part of #44 (closed) where all branches will pull base images from staging. This solved the problem of using non-prod images as base images for the edge cases where that's required, but now we have a requirement that they greylist file is updated to match the newest feature branch, which goes against the current workflow and breaks any master builds needed to be run for new patches that fix CVEs.

The fix for this is to only pull from the staging registry for edge cases, not for every branch, by setting a boolean value for the edge case pipelines.

Interested Party

CHT team who have edge cases where the base image isn't in prod

Acceptance Criteria

• Boolean value is used to determine if the build stage uses ironbank-staging for base images.

Definition of Done

• Documentation in place
• All MR's closed