This allows the container to be tagged with a user friendly image name
(e.g. `redis:3.2`) rather than the image ID (e.g.
`sha256:87856cc39862cec77541d68382e4867d7ccb29a85a17221446c857ddaebca916`).
Useful for human debugging, as well as some debugging and image scanning
tools.
This risks two bad changes:
1. Discrepancy in image resolution between docker and Nomad's image
loader.
* I checked the image creation paths in Nomad, and noticed that we
either pulled the image or inspect the image with the user provided
name.
2. A race in image tagging where the tag is modified between image
loading and container creation.
* I, personally, don't think this case is cause for concern, as it is
analogous to the task running a bit later. As long as the image is
still present, creating the container should be good.
Introduce a device manager that manages the lifecycle of device plugins
on the client. It fingerprints, collects stats, and forwards Reserve
requests to the correct plugin. The manager, also handles device plugins
failing and validates their output.
