Consider re-doing diagrams from images into text formats

[jajik]

Currently, we have several diagrams in our documentation that are imported as pictures (e.g. png here).

It would make sense to change these into a text based format like dot/graphviz or something else that is easier to modify and track.

[rhusar]

The natural choice would be https://github.com/asciidoctor/asciidoctorj-diagram but anything else is fine too.