Add opentherm_gw device support

[mvn23]

Breaking Change:

Breaks enabled sensor and binary_sensor entities, these are now disabled by default and can be re-enabled through the Devices panel.
Breaks entity_id of the climate entity in some configurations. The entity_id is now based on the gateway_id rather than the configured name to guarantee uniqueness.

Description:

Add device support to the opentherm_gw integration.

Related issue (if applicable): fixes #28378

Pull request with documentation for home-assistant.io (if applicable): home-assistant/home-assistant.io#11163

Example entry for configuration.yaml (if applicable):

N/A

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly. Update and include derived files by running python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt by running python3 -m script.gen_requirements_all.
• Untested files have been added to .coveragerc.

If the code does not interact with devices:
N/A

[MartinHjelmare]

Regarding the breaking change, as long as the unique_id remains the same, changing the default entity_id will not be a breaking change for existing users.