Add iptables to wireguard dependencies

[kprosise]

Added to apt command to install dependencies.

QA Steps: Checked that the package name is correct, checked rendered output. Ran linkcheck. No issues found.

This commit addresses FFTK-3454, "Documentation: Wireguard dependency"

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Overview

Adds missing dependency as reported by customer

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[doanac]

Docs for 1c3c5e8 are browsable at: https://ci.foundries.io/projects/fio-docs/builds/2761/docs/artifacts/html/index.html

[vanmaegima]

LGTM

[Tim-Anderson]

LGTM