add readme with cwl example

@caroott

I was not sure about the relative paths. Could you extend and maybe add instructions for the other CWL examples?

runs/README.md

+
+# CWL examples
+
+:bulb: Requires installation of a CWL runner and docker
+checkout CWL guides in the [DataPLANT Knowledge Base](https://nfdi4plants.org/nfdi4plants.knowledgebase/docs/guides/ComputationalWorkflows/index.html)
+
+All three workflow examples below (re)create the file [fsResult1/result.csv](fsResult1/result.csv).
+
+## with a docker container
+
+```bash
+cd runs/fsResult1
+cwltool ../../workflows/FixedScript/FSharpArcCapsule.cwl ../FSharpArcCapsule.yml
+```
+
+## With a fixed script in a mounted arc
+
+```bash
+cd runs/fsResult1
+cwltool ../../workflows/ARCMount/FSharpArcCapsule.cwl ../FSharpArcCapsule.yml
+```
+
+## Within an ARC with a devcontainer
+
+```bash
+cd runs/fsResult1
+cwltool ../../workflows/Devcontainer/FSharpArcCapsule.cwl ../FSharpArcCapsule.yml
+```