Document anticipated CLI entry points

[widal001]

Summary

Document the desired developer experience of the CommonGrants CLI for the following use cases:

• Setting up a CommonGrants project
• Validating a CommonGrants API spec for compliance with the base protocol
• Generating server code from a CommonGrants API spec
• Generating client code from a CommonGrants API spec

Acceptance criteria

• Tickets have been created for each of the user cases above
• Each ticket documents both a user story and a mock CLI entry point to demonstrate the expected developer experience

[widal001]

I created the following tickets to describe the desired behavior of the CLI.

• [CLI] Create cg init command #63
• [CLI] Create cg preview command #64
• [CLI] Create cg check spec command #28
• [CLI] Create cg check api command #65
• [CLI] Create cg add field command #60
• [CLI] Create cg generate client command #61
• [CLI] Create cg generate server command #62