feat: add TypeScript samples support

[kweinmeister]

This PR enables adding TypeScript samples without managing duplicate JS and TS versions.

• It uses the typeless-sample-bot to parse the .ts samples into .js in post-processing.
• OwlBot is needed to trigger the bot. owlbot.py runs the bot and updates the formatting. It bypasses the owlbot_main() flow that performs client library tasks.
• The migration of a small sample scheduler was included to test the process. Also, the existing appengine/typescript sample needed to be updated to reconcile with the root level .eslintrc.json.
• CONTRIBUTING.md was updated with TypeScript instructions.

[bcoe]

I think that owlbot-nodejs-mono-repo will have some unintended consequences, because it does things like updating the README.md and copying over templates.

What we can do is create a trimmed down version here that strips out the logic for templates, etc., and keeps just the typeless-sample bits.

[snippet-bot]

Here is the summary of changes.

You are about to add 2 region tags.

• scheduler/createJob.js:23, tag cloudscheduler_create_job
• scheduler/createJob.ts:23, tag cloudscheduler_create_job

You are about to delete 1 region tag.

• scheduler/createJob.js:24, tag cloudscheduler_create_job

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[miketrebilcock]

Was this removed intentionally, the documentation still refers to this as an option for running an custom build script: https://cloud.google.com/appengine/docs/standard/nodejs/running-custom-build-step#example

[matthewrobertson]

I am pretty sure this was a mistake. The docs are correct.

[matthewrobertson]

This change actually broke the ability to deploy to GAE. It now fails in the build phase with an error like:

ERROR: (gcloud.app.deploy) Error Response: [9] Cloud build cdec98ca-e4aa-4a97-bbfc-d5843c7ff8a3 status: FAILURE
> appengine-typescript@0.0.1 prepare
> npm run compile


> appengine-typescript@0.0.1 compile
> tsc -p .

sh: 1: tsc: not found
npm ERR! code 127
npm ERR! path /workspace
npm ERR! command failed
npm ERR! command sh -c -- npm run compile

npm ERR! A complete log of this run can be found in:

This is because the devDependencies are not installed when the prepare script is run. The gcp-build script fixes this.

[kweinmeister]

This change has been reverted, and a test with npm run deploy was successful.

[matthewrobertson]

FYI, we are currently working on a change to run npm run build by default when deploying to AppEngine, because this gcp-buildthing is not very intuitive.

cc @anniefu