OpenCLI schema support

[cmcgee1024]

• Add OpenCLI schema, Swift data types, and a test based on the example
• Create an OpenCLI generator that is invokable using '--help-dump-opencli-v0.1'
• Add unit tests and end-to-end tests
• Customize the OpenCLI data types to encode Swift Argument Parser specific extensions using swiftArgumentParser prefix for items like repeating options, and file/directory options/arguments

Checklist

• [X] I've added at least one test that validates that my change is working, if appropriate
• [ ] I've followed the code style of the rest of the project
• [X] I've read the Contribution Guidelines
• [ ] I've updated the documentation if necessary