Add typegen for workflow contexts to help using createWorkflow

[bkegley]

Adds a generate-types CLI tool that fetches workflow context schemas to generate type declarations to improve the type-safety of using createWorkflow

Usage

prism login
npx @prismatic-io/embedded generate-types -o prismatic.d.ts

Then add the generated file to your tsconfig.json:

{
  "include": ["prismatic.d.ts"]
}

Review Peculiarities

• export {} in generated output — required so TypeScript treats the file as a module augmentation rather than an ambient module declaration (which would replace the module's types entirely)
• Stable key interface deduping — distinct stableKeys that produce the same PascalCase type name (e.g. my-workflow and myWorkflow both → MyWorkflowContext) get suffixed as MyWorkflowContext1, MyWorkflowContext2. This is all internal to the module augmentation so it doesn't matter.
• Separate tsconfig for generators — tsconfig.generators.json compiles src/generators/ to CommonJS independently from the webpack build

[jpeters5392]

Would it be worth it to add proper argument checking here? In this case I could see checking that there is a next argument and it doesn't start with -, similar to how most of the other CLI parsing libraries handle it.

[bkegley]

That's good feedback. Swapped to node's built-in.