Add more Examples to Docs

[JensKrumsieck]

Create Examples of the following list items for our documentation (create sub-issue if needed)

• Create example using methods of Agricultural Sciences (target FAIRagro Researchers) -> provide demo with agro workflow m4.4_sciwin_client_examples#1
• Create example using methods of Plant Science or Biology
• Annotation of Workflows/Tools example
• Execution on REANA
• Insrallation of 3rd Party Workflows
• Subworkflows
• ... (please add)

Strategy:

• We create examples in a separate folder in the examples repo: https://github.com/fairagro/m4.4_sciwin_client_examples
• examples can be submoduled into it
• The folders contain the solved example, we instruct the reader to remove the workflows folder to begin with
• Always provide a sentence or two in the readme of the examples repo and also include the workflow visualization if a workflow is created.