Compliance Pipeline to Security Policy Migration Banner
### Problem to solve [Pipeline execution policies](https://docs.gitlab.com/ee/user/application_security/policies/#scan-execution-policy-schema) is adding support for [compliance framework pipelines](https://docs.gitlab.com/ee/user/project/settings/index.html#compliance-pipeline-configuration) to provide users need a single solution for enforcing jobs to be run as part of a project pipeline. Follow along with progress in this epic https://gitlab.com/groups/gitlab-org/-/epics/7312+ We are then providing users with step by step workflow for migrating from using Compliance Pipeline to utilizing custom yaml within Security Policies. Follow along with progress in this epic https://gitlab.com/groups/gitlab-org/-/epics/11275+ As discussed in the migration this will not be an automated process and there will undoubtedly be some compliance pipelines that will not get migrated (such as test projects). We need to create a solid strategy and messaging for these users and consider the behaviour for these cases. ### Proposal After https://gitlab.com/groups/gitlab-org/-/epics/12324+ the next phase of this is to add a banner altering users to the fact compliance pipelines are now in maintenance mode and a workflow to migrate to pipelines execution policies.
epic