example_light to be updated

The following modifications are needed:
1. setup thru the config flow instead of configuration.yaml
2. `ColorMode.RGB` usage example
3. async?
4. sample awesomelights?
5. add _attr_unique_id

Start by locating the example_light implementation and reviewing how its current configuration flow and examples work. Clarify the intended updates for setup through config flow, ColorMode.RGB, async support, sample awesomelights, and _attr_unique_id; done means the requested examples and implementation details are updated consistently.

Written by the indexing model from the issue text.