Add documentation about running cwltool from jupyter notebooks

[jvdzwaan]

Workflows can be run from jupyter notebooks using:

%%bash 
cwltool /home/jvdzwaan/cwl-working-dir/add_multiply_example_workflow.cwl --num1 2 --num2 3

[jvdzwaan]

Or using a cwltool Factory? (needs to be tested)

https://github.com/common-workflow-language/cwltool#import-as-a-module