Group Access Token availability on GitLab.com SaaS is unclear (docs, settings)

Proposal

The availability of Group Access Tokens is unclear in the docs, and group settings.

The documentation hides the availability in a long text block, which seems hard to digest and parse. The group settings show the feature to configure, with no clear error messages on the why.

The group settings show the feature available, when it should not.

This leads to user frustration, and many questions in the community forum in this topic: https://forum.gitlab.com/t/gitlab-impossible-to-enable-group-access-token/81540

Suggested fixes

• Modify the Product Tier banner in the documentation, and say that Group Access Tokens are only available on GitLab.com SaaS in Premium/Ultimate.
• For Free Tier users: Modify the group settings on GitLab.com SaaS, grey them out and add a note linking to /pricing UX guidance is to hide features that are not available to users, e.g. through a subscription. https://design.gitlab.com/usability/feature-management#visibility
• Update the UI copy on the Access tokens page: The current copy on the page is confusing in the situation where a group previously had created access tokens but no longer has creation access to the feature (like when a paid plan expires). See current and proposed copy (pending TW feedback)

/cc @hsutor @jglassman1