Feature: HA Update entities for containers

[nilsbyte]

Home Assistant has Update Entities (https://developers.home-assistant.io/docs/core/entity/update/) which indicate if an update is available for a device or service.

There are two different ways these would work:

• If the Update entity has the ability to not only check but also update the device/service:
  The entity shows up in the HA settings dashboard as available update.

• If the Update Entity has no ability to update the device/service:
  The entity shows up in the HA settings under Settings > System > Updates as "not installable updates".

For this feature request, it would be good to have the first case, an update entity that allows updating the corresponding docker container.