Add link to region docs

[shainaraskas]

Added docs for serverless cloud regions here - this PR adds an informational link for regions to the security project creation doc.

I also removed the region proximity guidance from this on request. the linked region page provides some similar guidance, just a little less prescriptive

Won't merge until the core doc is merged

[github-actions]

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[mergify]

This pull request does not have a backport label. Could you fix it @shainaraskas? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• v7.x is the label to automatically backport to the 7.x branch.
• v7./d./d is the label to automatically backport to the 7./d branch. /d is the digit

NOTE: backport-skip has been added to this pull request.

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[joepeeples]

LGTM!