Add new connectivity overview page

[pipo02mix]

What this PR does / why we need it

Towards https://github.com/giantswarm/giantswarm/issues/30732

Things to check/remember before submitting

• If you made content changes

  • Run make dev to render and proofread content changes locally.
  • Bump last_review_date in the front matter header if you reviewed the entire page.

[pipo02mix]

It is a draft, I just marked it now. I have created a ticket to explain what is the purpose of this doc entry. I am hesitating if we need just an outline or we (as sig docs participants) can further facilitate the article's writing. Now the body contains the template outline and some suggestions on how to write it. My thinking was to let the champion write the draft and help him later with wording and syntax to be consistent and similar to other sibling pages. WDYT?

[AndiDog]

It is a draft, I just marked it now. I have created a ticket to explain what is the purpose of this doc entry. I am hesitating if we need just an outline or we (as sig docs participants) can further facilitate the article's writing. Now the body contains the template outline and some suggestions on how to write it. My thinking was to let the champion write the draft and help him later with wording and syntax to be consistent and similar to other sibling pages. WDYT?

I think SIG Docs could provide an outline, but then again the champion is the expert of what should even be included in the article (whether it's in "Overview" or "Getting started", doesn't matter). Getting together online to draft an outline could work, instead of trying that asynchronously (which might be slower).