Include docstrings for individual schemas

[jaypipes]

We should include docstring comments for fields in the generated type definition and CRD definition output. This documentation is available in the aws-sdk-go's doc.json files (and I've included some of those documentation strings for things like API operations in the output from aws-api-tool schema). I just need to figure out the mapping system that the doc.json files use for referring different references of same-named fields to different docstrings