* For #5799: add architecture document outline for review
* For 5799: update architecture doc outline
- Remove references to old architecture (Soon it will all have been replaced. No need for the additional cognitive load)
- Add some subheadings
- 'Simplified Example' seems like a good idea. Update the language to clarify that it will be done
* For 5799: add additional known limitations
* For 5799: wrote first draft for architecture 'overview' and 'important objects'
* For 5799: wrote first draft for arch doc 'important notes'
* For 5799: wrote arch doc 'known limitations' section
* For 5799: wrote example code for architecture doc
* For 5799: added example app wireframe for arch docs
* For 5799: update arch docs 'Simplified Example section'
* For 5799: improve formatting for architecture docs
* For 5799: minor tweaks to architecture docs
* For 5799: link 'simplified example' section to example code
* For 5799: update arch doc per review
