Add CORS configuration

[feedmeapples]

What was changed

Adds CORS configuration:

dockerize variable TEMPORAL_CORS_ORIGINS (or directly through the config file)

• default is http://localhost:$TEMPORAL_UI_PORT`
• development mode also white lists http://localhost:3000 through development.yaml

Why?

• Allows to set up other CORS origins instead of hardcoded localhost:3000

Checklist

1. Closes

2. How was this tested:

docker run --network host -e TEMPORAL_CORS_ORIGINS=http://localhost:3000 temporaliotest/ui

3. Any docs updates needed?

Updated docker README

[stevekinney]

Perfect. This is way better than what we had.