Deprecate name property of unit system

[epenet]

Breaking change

The name of a unit system should never be used for checking its type. Instance checks should be used instead:

Correct:

if hass.config.units is IMPERIAL_SYSTEM:
    pass

if hass.config.units is METRIC_SYSTEM:
    pass

Incorrect:

if hass.config.units.name == CONF_UNIT_SYSTEM_IMPERIAL:
    pass

if hass.config.units.name == CONF_UNIT_SYSTEM_METRIC:
    pass

Proposed change

Deprecate the name property, and log a warning if it is accessed.

Linked PRs:

• Adjust distance unit check in google travel time #80232
• Adjust get_distance_unit in mazda integration #80233
• Adjust distance unit check in gdacs #80235
• Adjust distance unit check in geonetnz_quakes #80236
• Adjust temperature unit check in rainmachine #80237
• Adjust distance unit check in waze travel time #80241
• Adjust distance unit check in here travel time #80243
• Adjust distance unit check in geonetnz_volcano #80244

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• 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: Blog post for deprecated unit system features developers.home-assistant#1496

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• The code has been formatted using Black (black --fast homeassistant tests)
• 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

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

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• For the updated dependencies - a link to the changelog, or at minimum a diff between library versions is added to the PR description.
• Untested files have been added to .coveragerc.

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[emontnemery]

LGTM 👍