* fix plugin launcher SetConfig msgpack params
The plugin launcher tool was passing the wrong byte array into
`SetConfig`, resulting in msgpack decoding errors. This was fixed in
a949050 (#6725) but accidentally reverted in 6aff18d (#6590).
Co-Authored-By: Chris Baker <1675087+cgbaker@users.noreply.github.com>
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.
This PR introduces:
* An example device plugin that exposes files as devices for testing.
* Helpers for serving a device plugin
* A launcher binary that allows interacting with a device plugin without
needing a Nomad client.