Embed lava-coordinator configuration in dispatcher message
There is no need for workers to have a lava-coordinator configuration file once the integration is complete.
Include the (tiny) snippet of configuration for lava-coordinator into the parsed YAML sent to the dispatchers for each job using the multinode protocol.
Allows a second coordinator to be added to an instance - e.g. for debugging or service continuity.
Migrated from https://projects.linaro.org/browse/LAVA-196