Improve UX for Auto DevOps and deploy tokens interaction

Description

We have deploy tokens (https://gitlab.com/gitlab-org/gitlab-ce/issues/31591), and if you create the right one it is automatically exposed to CI/CD jobs (https://gitlab.com/gitlab-org/gitlab-ce/issues/44447), so Auto DevOps can use it (https://gitlab.com/gitlab-org/gitlab-ce/issues/44451).

The missing part is that users should be aware of this.

Proposal

Make the flow simple and clear to users that are using Auto DevOps, but that don't know about the need of deploy tokens and how to use them. We should make users aware both in the Kubernetes page and in the Auto DevOps page.

We can either provide links to the Deploy Token page, and explain there what they should do, or provide an automated way to create the token they need for Auto DevOps.