Add speed to SensorDeviceClass

[epenet]

Proposed change

Add new speed device class Linked to https://github.com/home-assistant/architecture/discussions/798

• [x] Frontend: https://github.com/home-assistant/frontend/pull/13832
• [x] Developer docs: https://github.com/home-assistant/developers.home-assistant/pull/1466
• [x] User docs: https://github.com/home-assistant/home-assistant.io/pull/24066

Needs:

• [x] #77952
• [ ] #78578

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

• [ ] 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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• [ ] I have reviewed two other open pull requests in this repository.

[probot-home-assistant[bot]]

Hey there @home-assistant/core, mind taking a look at this pull request as it has been labeled with an integration (sensor) you are listed as a code owner for? Thanks! _{^{(message by CodeOwnersMention)}}

[IceBotYT]

This would fix #78007

[pvizeli]

Nice. Will add it to ecowitt and homematic then

[homeassistant]

Hey there @home-assistant/core, mind taking a look at this pull request as it has been labeled with an integration (recorder) you are listed as a code owner for? Thanks!

[epenet]

Rebased over #77951