[RUM-9982] Set up React Native babel plugin project

[cdn34dd]

What does this PR do?

Sets up new project consisting of a babel plugin, aiming to make React Native's sdks work more seamlessly.

In it's current state, it has the basic file structure in place and it's already integrated into the workspace. It also sets up a flag when integrated on a React Native app, that will later on be used to add Telemetry and to allow the code to choose whether to rely on the babel plugin for RUM actions or to rely on the current approach.

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests
• Make sure you discussed the feature or bugfix with the maintaining team in an Issue
• Make sure each commit and the PR mention the Issue number (cf the CONTRIBUTING doc)
• If this PR is auto-generated, please make sure also to manually update the code related to the change

[datadog-datadog-prod-us1]

Datadog Report

Branch report: carlosnogueira/RUM-9982/setup-base-package-for-babel-plugin
Commit report: 4a79ad0
Test service: dd-sdk-reactnative

✅ 0 Failed, 661 Passed, 1 Skipped, 8.16s Total Time

[marco-saia-datadog]

Great work! 🙌 I am approving this because I believe the points I have raised in my comments are non-blockers at this stage

[marco-saia-datadog]

Actually, we do have a blocker, as checks are failing.

I believe the problem is the missing tsconfig.json in the react-native-babel-plugin folder:

> @datadog/mobile-react-native-babel-plugin:prepare
ℹ Building target commonjs
ℹ Cleaning up previous build at lib/commonjs
ℹ Compiling 9 files in src with babel
✔ Wrote files to lib/commonjs
ℹ Building target module
ℹ Cleaning up previous build at lib/module
ℹ Compiling 9 files in src with babel
✔ Wrote files to lib/module
ℹ Building target typescript
ℹ Cleaning up previous build at lib/typescript
ℹ Generating type definitions with tsc
✖ Couldn't find a tsconfig.json in the project root.