Add Browse Media to Xbox

[hunterjm]

Proposed change

This adds browse media to the Xbox media player allowing users to navigate to the Dashboard, Live TV (if configured on the device), or launch any installed app or game.

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)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Example entry for configuration.yaml:

# Example configuration.yaml
xbox:
  client_id: !secret xbox_client_id
  client_secret: !secret xbox_client_secret

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: Add Xbox documentation home-assistant.io#15223

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.
• Untested files have been added to .coveragerc.

The integration reached or maintains the following Integration Quality Scale:

• No score or internal
• 🥈 Silver
• 🥇 Gold
• 🏆 Platinum

To help with the load of incoming pull requests:

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

[MartinHjelmare]

Directories should have media class directory and children media class corresponding to the directory content.

[MartinHjelmare]

Looks good!

[hunterjm]

Do I need separate docs for the browse media feature, or is home-assistant/home-assistant.io#15223 sufficient?

[MartinHjelmare]

We can extend that docs PR, if it's not ready for merge yet. We should probably document the play media service, ie what media content type and media content id is accepted. The browse media feature doesn't need to be documented as such.

[hunterjm]

Docs PR updated. LGTM!