Advanced Support Topics - correct orphaned links, use issuable templates

Why is this change being made?

The list Earn the Expert badge by completing any of these modules had some orphaned links (Kubernetes, CI) so this MR fixes those. This also adds a link, since the Kubernetes training module was split into two parts. While working on fixing those I also decided it made sense to implement issuable templates in the links, so I updated all of the relevant links in that list accordingly.

Questions raised by this MR

• Is there a way we can check for orphaned links when pages are being changed in the handbook, so we can avoid this happening in the future?
• Should any handbook page that refers to an issue template have the link updated from a link to the template itself to a link to create a new issue using that template, where appropriate? (i.e. when the link is intended for someone to create an issue rather than to edit the template itself)

Author Checklist

• Provided a concise title for this Merge Request (MR)
• Added a description to this MR explaining the reasons for the proposed change, per say why, not just what
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• If the changes affect team members, or warrant an announcement in another way, please consider posting an update in #whats-happening-at-gitlab linking to this MR
  • If this is a change that directly impacts the majority of global team members, it should be a candidate for #company-fyi. Please work with internal communications and check the handbook for examples.

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