* Fix CID file handling to prevent directory creation
It seems that under certain conditions Docker creates a directory
instead of a file for the CID file. This change ensures that
the CID file is always created as a file, and any existing directory
is removed before creating the file.
* Fix tests
* Fix pytest
* Write cidfiles of Docker containers and mount them individually to /run/cid
There is no standard way to get the container ID in the container
itself, which can be needed for instance for #6006. The usual pattern is
to use the --cidfile argument of Docker CLI and mount the generated file
to the container. However, this is feature of Docker CLI and we can't
use it when creating the containers via API. To get container ID to
implement native logging in e.g. Core as well, we need the help of the
Supervisor.
This change implements similar feature fully in Supervisor's DockerAPI
class that orchestrates lifetime of all containers managed by
Supervisor. The files are created in the SUPERVISOR_DATA directory, as
it needs to be persisted between reboots, just as the instances of
Docker containers are.
Supervisor's cidfile must be created when starting the Supervisor
itself, for that see home-assistant/operating-system#4276.
* Address review comments, fix mounting of the cidfile
