Add version compatibility note (experimental vs. stable) for the new registration method

Description

Certain versions of runner will not be compatible with the new registration method, we should notify inform the user about these changes:

• Up to gitlab-runner 15.9, the new registration flow does not work
• From gitlab-runner 15.10, the new registration flow works, but it is experimental
• From gitlab-runner 16.0, the new registration flow is recommended

Proposal

• See designs in design management
• Figma file