Set up app for Jetpack's support bot integration

[ice9js]

Suprecedes #94082.

Proposed Changes

Adds a jetpackme-support app which will serve as the home for the Odie support widget on https://jetpack.com/contact-support.

Why are these changes being made?

• pcKp4R-C6-p2

Testing Instructions

• Run yarn dev to test whether everything builds correctly.

Note that so far this doesn't affect any page in production.

Pre-merge Checklist

• Has the general commit checklist been followed? (PCYsg-hS-p2)
• Have you written new tests for your changes?
• Have you tested the feature in Simple (P9HQHe-k8-p2), Atomic (P9HQHe-jW-p2), and self-hosted Jetpack sites (PCYsg-g6b-p2)?
• Have you checked for TypeScript, React or other console errors?
• Have you used memoizing on expensive computations? More info in Memoizing with create-selector and Using memoizing selectors and Our Approach to Data
• Have we added the "[Status] String Freeze" label as soon as any new strings were ready for translation (p4TIVU-5Jq-p2)?
• For changes affecting Jetpack: Have we added the "[Status] Needs Privacy Updates" label if this pull request changes what data or activity we track or use (p4TIVU-aUh-p2)?

[github-actions]

Calypso Live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-120869

Jetpack Cloud live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-120869&env=jetpack

Automattic for Agencies live (direct link)

https://calypso.live?image=registry.a8c.com/calypso/app:build-120869&env=a8c-for-agencies

[matticbot]

Here is how your PR affects size of JS and CSS bundles shipped to the user's browser:

App Entrypoints (~8 bytes added 📈 [gzipped])

name                   parsed_size           gzip_size
entry-subscriptions          +22 B  (+0.0%)       +8 B  (+0.0%)
entry-stepper                +22 B  (+0.0%)       +8 B  (+0.0%)
entry-main                   +22 B  (+0.0%)       +8 B  (+0.0%)
entry-login                  +22 B  (+0.0%)       +8 B  (+0.0%)
entry-domains-landing        +22 B  (+0.0%)       +8 B  (+0.0%)

Common code that is always downloaded and parsed every time the app is loaded, no matter which route is used.

Legend

What is parsed and gzip size?

Parsed Size: Uncompressed size of the JS and CSS files. This much code needs to be parsed and stored in memory.
Gzip Size: Compressed size of the JS and CSS files. This much data needs to be downloaded over network.

Generated by performance advisor bot at iscalypsofastyet.com.

[ice9js]

I verified that this builds correctly and produces a working result. As for the actual contents of the entrypoint, we'll likely change that later as well as the way the client mounts onto the page, so no need to pay a lot of attention to that just yet.

[anomiex]

Infrastructure seems reasonable. I didn't test it or look into the JS code.

[anomiex]

I wonder if this is still needed after WordPress/gutenberg#65292. Depends on whether @wordpress/babel-preset-default is used I think.