feat: add a local gRPC coordinator harness

the coordinator/harness/exporter packages have been
refactored to support the new gRPC coordinator approach
that is now being taken in the `Labgrid` project.

The handling of the subprocess calls has been simplified
and there are a number of changes to support the new output
and parameters that can be provided to the coordinator and
exporter.

The harness test has also been tweaked to allow it to test
the functionality correctly.

large portions of the crossbar related functionality is also
removed as it is no longer necessary along with the additional
requirements and python pip related code.