Add information about reference architectures for deployable architectures

[SirSpidey]

Add information to the docs and to the module-template to provide structure and guidance for how to include a reference architecture.

Include links to Cloud docs (only in test).

Tasks

• Add optional Reference architecture section to module-template readme file
• Add a markdown template to the Docs
• Docs: Add reference architecture to the module structure page.
• Docs: Add a Reference architecture section to the Authoring guidelines page.