Add distinction between DNS Aliases for Direct Mode vs NAT Mode to
describe the feature in ar71xx PR#573.
Include small format changes for firmware install steps.
Include note for tunneling using nodes with built-in switches.
Minor formatting tweaks.
Minor formatting changes on Installing Firmware.
Minor formatting changes to four sections, making formats consistent
across sections.
Format Install Firmware section consistently.
More formatting consistency checks in additional doc sections.
Added Network Design Guide sections, and edited a few Getting Started Guide areas. Both guidebooks are now part of the single existing AREDN documentation repository.
Steve AB7PA