Passthrough mode

Enables the pipeline to run without a repository for every individual vendor image from one project.

• Ensure linked bootstrap and bootstrap values MR's are merged and applied.

• At the DSOP group level ensure the CI/CD variable (env_var) PASSTHROUGH_SIDECAR_LABEL exists with a value of mode=ironbank or the build job will fail for all non passthrough images. The IaC sets this var for each vendor project appropriately.

• Clearly labeled chore tickets will be created for each image with un-verified findings in VAT, and will behave the same was as DSOP chore tickets.