Draft: Add disqus comments template

We've been monitoring the feedback from "disqus" comments (comments made by user on pages on docs.gitlab.com by selecting the Show and post comments option) over the last quarter (since 2021-10-29).

These comments are holding steady at low volumes of approximately 2 comments per month.

This template gives us a consistent way to capture, action, or re-route the comments.

Related issues or MRs

• Disqus as user commenting tool for docs.gitlab.com https://gitlab.com/groups/gitlab-org/-/epics/6670

• Ensure existing documentation feedback issues are triaged https://gitlab.com/gitlab-org/gitlab/-/issues/227858