Bug Fix: Setting the WEBSOCKET_URL var prod and dev

[david-macpherson]

Relevant components:

• Scalable Pixel Streaming Frontend library
• Examples
• Docs

Problem statement:

If building for Prod the WEBSOCKET_URL supplied by the .env will be still be bundled into the generated files
The value of the WEBSOCKET_URL should only be bundled if built for dev

Solution

Move the logic for setting the WEBSOCKET_URL from the .env file to the webpack dev configuration
Set the WEBSOCKET_URL to undefined when building for prod

Documentation

Test Plan and Compatibility

Built for dev while setting the WEBSOCKET_URL var in the .env file and ensured the frontend was connecting to the supplied value
Built for dev without setting the value in the .env file and deployed to an sps install and ensured it was connecting to the generated websocket address
Built for prod while setting a value in the .env value and ensured it was connecting to the websocket generated address

[lukehb]

lgtm