Deprecation banner for compliance pipelines

Description

Create a deprecation and removal notice once we have a clear migration path to notify users of planned deprecation of compliance pipelines as security policies will support custom yaml and enable users to define/enforce custom jobs more granularly.

Implementation plan

Behind a feature flag add a notification around compliance framework pipelines forms to notify users of an incoming maintenance mode change.

Compliance center > Frameworks Tab
before: https://gitlab.com/gitlab-org/gitlab/blob/master/ee/app/assets/javascripts/compliance_dashboard/components/frameworks_report/report.vue#L95

add banner to nudge to migrate pipeline to policy when edit a compliance framework
https://gitlab.com/gitlab-org/gitlab/blob/master/ee/app/assets/javascripts/compliance_dashboard/components/frameworks_report/edit_framework/edit_framework.vue#L358

Reference designs here: #423725 (designs)