chore: add scenario and diagram docs (#522)

* add diagram for scenario (stackabletech/issues#524)

* add WIP scenario

* fix: markdown formatting

* add a robot

* fix typo

Co-authored-by: Andrew Kenworthy <[email protected]>

* split diagrams to display the correct page

* add middle initials to persona names

* refine the marketing team description

* added some arrows/DMZ

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Co-authored-by: Andrew Kenworthy <[email protected]>

Author: NickLarsenNZ