Improve documentation of OGC application packaging

[mcduffie]

Improve documentation available describing the OGC Application Package standard as implemented by Unity.

Overview of OGC Application Package Process: Provide an overview of the OGC application package, including the CWL format/specification.

Best Practices: Document best practices for using/writing CWL, assuming users do not utilize the app-pack-gen and without JupyterHub, and highlight common user confusions or mistakes.

Examples: Offer multiple examples demonstrating the OGC processing in various scenarios, with step-by-step procedures and accompanying screenshots or diagrams where applicable. Note that a user guide currently exists in GitBook but needs more examples tailored towards CWL without using JuyterHub and app-pack-gen.

Given a Docker container, how would you put together CWL to run it (stage-in/stage-out/process/workflow)