DOCS: please provide a full config file with all options available for quick perusal

[codekiln]

Is your feature request related to a problem? Please describe.
I'm often trying to figure out if feature XYZ is supported in the config file in the latest version of aws_okta_keyman. Today I wanted to figure out if I could specify a role or an account, and an LLM couldn't answer immediately other than to say that the CLI flags were available.

Describe the solution you'd like
A sample config.yml is placed in the repository with comments explaining the options.