Build Typescript and migrate StripeResource

[anniel-stripe]

Summary

r? @kamil-stripe

This PR starts the process of migrating stripe-node to Typescript through the following steps:

1. Move files from lib/ to src/ directory
2. Configure TypeScript compilation through tsconfig.json, outputs into lib/
3. Add build and prepack script for Typescript compilation
4. Add step in CI/CD to build Typescript
5. Begin migrating existing stripe-node infrastructure to TypeScript with StripeResource, add linting overrides for .ts files

Testing

Validated that build, lint, and test scripts pass locally. Compared previous StripeResource.js to compiled lib/StripeResource.js to make sure that there are no unexpected changes.

With this change, the published NPM package will only contain the transpiled Javascript code in lib/. Our tests still import from/lib/*.js, and pass with this change.

[kamil-stripe]

LGTM. @dcr-stripe for quick double check?

[dcr-stripe]

LGTM overall - great work Annie! Just left some minor comments.

Let's:

1. Set up the corresponding PR to start code-generating at src/ instead of lib/ and re-run codegen in this branch to make sure it's a no-op before merging this.
2. Document our testing plan in this PR ie. how do we make sure the artifact we publish to NPM after this is still valid JS and compatible with existing integrations (both for JS and Typescript)

r? @anniel-stripe

[anniel-stripe]

LGTM overall - great work Annie! Just left some minor comments.

Let's:

1. Set up the corresponding PR to start code-generating at src/ instead of lib/ and re-run codegen in this branch to make sure it's a no-op before merging this.
2. Document our testing plan in this PR ie. how do we make sure the artifact we publish to NPM after this is still valid JS and compatible with existing integrations (both for JS and Typescript)

r? @anniel-stripe

1. Just submitted the PR!
2. The NPM package will only contain the transpiled Javascript code in lib/, which is what is being used in the tests (imports from /lib/*.js. All of these tests pass with this change. Will update the PR description.

[dcr-stripe]

LGTM!