Add documentation on how to create a file and attach it to a resource using a workflow

[katrinDY]

Where to add content

https://github.com/cortezaproject/corteza-docs/tree/2022.9.x/src/modules/integrator-guide/pages/automation/workflows/examples

TODO:

• read forum discussion https://forum.cortezaproject.org/t/workflow-create-file-and-attach-it-to-a-resource/697
• add to the docs https://forum.cortezaproject.org/t/workflow-create-file-and-attach-it-to-a-resource/697/2

Notes:

• Structure the document appropriately
• Add screenshots if needed