Client documentation contains invalid json example

[de-jcup]

https://daimler.github.io/sechub/latest/sechub-client.html#upload-sources-from-file-system

shows a invalid and not well formatted JSON example.

Refactor 02_sechub_client.adoc in following ways:

• change all parts being json to be included as json files
• validate those files and format them!
• move away from code2doc folder (its not generated!)

[de-jcup]

Many parts where already refactored in former commits, so most examples now as json file available and so ensured its valid.