New design guide: Securing guest wireless networks (#18820)

* New design guide

* Apply suggestions from code review

Co-authored-by: Maddy <[email protected]>

* Apply suggestions from code review

Co-authored-by: hyperlint-ai[bot] <154288675+hyperlint-ai[bot]@users.noreply.github.com>

* Update securing-guest-wireless-networks.mdx

* Update securing-guest-wireless-networks.mdx

* Update src/content/docs/reference-architecture/design-guides/securing-guest-wireless-networks.mdx

Co-authored-by: hyperlint-ai[bot] <154288675+hyperlint-ai[bot]@users.noreply.github.com>

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Co-authored-by: Maddy <[email protected]>
Co-authored-by: hyperlint-ai[bot] <154288675+hyperlint-ai[bot]@users.noreply.github.com>

Author: 3 people