Media Source implementation for Chromecast

[hunterjm]

Proposed change

This PR implements a relatively simple new integration that exposes media files found in allowlist_external_dirs with a media browser compatible API through a new /media view behind auth. It also creates a new websocket for media_finder/browse_media which along with auth/sign_path will allow for a lovelace card to be developed to play local media files in the browser. The name for the integration is still up in the air, so feel free to vote for one.

Here I also implement Media Browser for the cast integration since Chromecast allows playing of arbitrary URLs. To pass auth, we sign the path with the Home Assistant Cast user with a 5 minute expiration.

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:

media_finder:

or

default_config:

Additional information

• This PR fixes or closes issue: N/A
• This PR is related to issue: Enables a card to be developed for https://community.home-assistant.io/t/wth-play-recorded-mp4-video-in-frontend/221696
• Link to documentation pull request: Add docs for media_source home-assistant.io#14396

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
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• 🥇 Gold
• 🏆 Platinum

To help with the load of incoming pull requests:

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

[balloob]

Suggested change

	await self.hass.async_add_job(
	await self.hass.async_add_executor_job(

[MartinHjelmare]

This wasn't addressed.

[hunterjm]

Sorry, I thought Paulus addressed it in his followup commits. Either way, this is exactly what the parent does.
https://github.com/home-assistant/core/blob/dev/homeassistant/components/media_player/__init__.py#L600-L604

I can add a follow-up PR to change it there and simply call super in this class if you would like.

[MartinHjelmare]

Yes, please. 👍