Auth + Hass.io: create system user

[balloob]

Hass.io supervisor communicates with Home Assistant via the API. This needs to be adopted for the new auth system.

At startup, the Hass.io component should:

• create a client. Should be marked as system-generated and cannot be deleted. Should also be marked that it cannot be used for any logins?
• create a user. Should too be marked as system-generated and cannot be deleted. Should have 0 linked credentials so that it cannot be used to login with.
  -create a refresh token and share it with the supervisor

Should the refresh token have a very long expiration so that Hass.io never needs to refresh? If so, should we just send the access token?

[awarecan]

We should have scope and issuer property for token/client. In future we can use scope: even more fine grained control access. We can use issuer to decided if user can manage them.

[balloob]

Eventually I want to add those. Don't think that they will be needed to implement system users.