docs: add @swmansion/t-rex-ui

[kacperkapusciak]

Description

Because of a ramping up maintainance cost across our suite of tools - Reanimated, Gesture Handler & React Native IDE we've decided to create a UI library for our reusable docusaurus components.

The @swmansion/t-rex-ui package aims to unify the components across our documentations. This will make the maintainance easier in the long term by code reuse. We hope that with a single source of truth will avoid the need of fixing a bug in 3-4 places instead of just one.

Sidenote: the package requires the React & ReactDOM in version 18 or higher.

Test plan

cd docs/
yarn

# to test development build
yarn start

# to test production build
yarn build
yarn serve