[Backend] Include variables_override in the job logs

Why are we doing this work

It's important to have visibility for the jobs where the variables precedence is controlled by the policies. It will make our lives easier / prevent many support tickets if we can have more information about how policies impact other parts of the product.

1. We should add a log message for the jobs for policy jobs:

   Job xxx triggered by {policy_name}

2. We should log if variables have been altered. See the design for various versions, depending on the variables_override configuration:

   Policy denies any CI variable from overwriting this job.

Relevant links

• Design Issue
  • Job page

Implementation plan

Verification steps