Include start from pulled projects

[josephjclark]

• Fix how the CLI currently reads workflow.yaml files to support the options key
• Fix how project currently serialises yaml files (use workflow, options)
• Write a start to all workflows when pulling from state
• Ensure workflow start is properly serialized to v2

When done, this will change the structure of workflow files on disk, and enable openfn execute to work on pulled workflows.

Fixes #1204

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[josephjclark]

Ok, so this whole implementation is wrong.

• We need to drop the { workflow, options } structure
• We should default the trigger to the first step
• We should support a first class start key on a workflow structure
• The project file and workfow.yaml should both have an options key, which is probably unused