Banner to enable Auto DevOps when Admin logs in

When an admin logs in, it would be helpful to add a banner asking if they want to enable the Auto DevOps feature (that otherwise will be off by default). The banner should be dismissible.

This is an iteration off of https://gitlab.com/gitlab-org/gitlab-ce/issues/34777

Design

Banner:

edit: text should mention "all projects"

Svg: autodevops-illustration.svg

Places to put it:

• Admin dashboard
• Projects overview (will override/higher priority than customize your experience banner)