Revisit use-cases & advanced-developer-use-cases chapters ambiguity

[domhanak]

The use-cases & advanced-developer-use-cases is a bit counter intuitive as we do not have any other use cases there.
Intention was to have also advanced use case without java and for Administrator persona there in the future.

Goal
Revisit the section to make the chapters more intuitive.

[domhanak]

Idea for implementation:

• use-case | Contains signpost for all different personas | non-java dev | java dev | administrator
  -- advanced-developer- use-cases | java dev
  -- advanced-use-cases | non java dev
  -- advanced-administrator-use-case | administrator of cluster

Ofc these need to be populated, with something.

@krisv @ricardozanini

[ricardozanini]

non java dev we can replace with workflow developer, wdyt?