feat(React Incubation): React Playground Proof of Concept

[jjoyce0510]

This PR includes a React proof-of-concept under a new 'datahub-web-react' module. I chose to locate it there instead of /contrib because I've been testing serving this from datahub-frontend and gradle modules are required for that!

Take a look around, explore! To run the mock server, run yarn run start from inside the datahub-web-react module. As of now, we are simply mocking GraphQL response data using Apollo MockProvider. You can find the request-response mocks under Mocks.tsx in /src directory. This can be changed using a variable in App.tsx if you want to hit a local datahub-frontend (but must have /graphql endpoint changes from my prev PRs).

You'll notice that the reason we can work with type-safe GQL bindings is because I've provided a temporary GQL schema file directly within the react app directory (datahub-frontend.graphql). Once the other pending GQL PRs are in, this will be replaced by the .graphql file inside /datahub-frontend.

Currently, most requests simply won't return any mocked data, try navigating to the following paths to see some content:

localhost:3000/logIn
localhost:3000/datasets/urn:li:dataset:1
localhost:3000/search?type=dataset&query=test

Notice that this is a major work-in-progress, many components need to be cleaned up & iterated on. Specifically we'll need to address styling convention (currently inlining styles, ew), testing convention, design, how we permit configurability / extensibility & more.

Some fun screenshots!

Checklist

• The PR conforms to DataHub's Contributing Guideline (particularly Commit Message Format)
• Links to related issues (if applicable)
• Tests for the changes have been added/updated (if applicable)
• Docs related to the changes have been added/updated (if applicable)

[jjoyce0510]

The architecture / layout of the components shown as of today are not the final proposal. One interesting thing to consider further is how 'entity-oriented' we should go. The existing Ember app provides Entity classes where details, search, & browse information is all located. Following a similar pattern here should be considered!

[shirshanka]

Build is green. Approving and merging in, so community can play with it, while we can iterate on further design and extract common components from Ember app with LI team.