Meet requirements for Platinum-level Integrations

[strawgate]

• Verify we meet all component requirements https://developers.home-assistant.io/docs/creating_component_code_review/
• Verify we meet all Silver requirements https://developers.home-assistant.io/docs/integration_quality_scale_index/
• Verify we meet all Gold requirements https://developers.home-assistant.io/docs/integration_quality_scale_index/
• Verify we meet all Platinum requirements https://developers.home-assistant.io/docs/integration_quality_scale_index/

[legrego]

I self-certified Gold in #199, but it looks like the requirements have changed even since then.

Full test coverage for the config flow

I don't know of "full" means 100% code coverage, or if there's a different definition here.

When communicating with a device or service, the integration implements the diagnostics platform which redacts sensitive information.

This one is new to me, and will need a bit more research.