Add support for extra people attributes

[Megabytemb]

Breaking change

Proposed change

This PR adds the ability to add adhoc attributes to a person entity. This is useful for automations where you want to send a text message, or email to a person entity.

This only adds support for yaml based config. The Websocket creation would support the extra field, but I didn't want to update the frontend before getting the all OK on this PR.

Example yaml config would be

person:
- name: Michael
  id: michael
  device_trackers:
    - device_tracker.michaels_s20
  extra_attributes:
    address: "123 Fake St"
    email: "[email protected]"
    phone: "316020387"

This makes for cleaner automations and templates. If you wish to reject this PR, please provide an alternative way of storing bespoke data on home assistant entities.

Thanks!

Type of change

• [ ] Dependency upgrade
• [ ] Bugfix (non-breaking change which fixes an issue)
• [ ] New integration (thank you!)
• [x] New feature (which adds functionality to an existing integration)
• [ ] Deprecation (breaking change to happen in the future)
• [ ] Breaking change (fix/feature causing existing functionality to break)
• [ ] Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• [x] The code change is tested and works locally.
• [x] Local tests pass. Your PR cannot be merged unless tests pass
• [x] There is no commented out code in this PR.
• [x] I have followed the development checklist
• [x] I have followed the perfect PR recommendations
• [x] The code has been formatted using Black (black --fast homeassistant tests)
• [x] Tests have been added to verify that the new code works.

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

• [ ] Documentation added/updated for www.home-assistant.io

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  Updated and included derived files by running: python3 -m script.hassfest.
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  Updated by running python3 -m script.gen_requirements_all.
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