Make `labgrid-client` work with local-only configuration

[flxzt]

Currently it is only possible to use the labgrid-client tool with the distributed infrastructure - deployed exporter, coordinator, and so on.

When trying to use labgrid-client with only a local environment configuration where no remote place is specified and no coordinator address is supplied, the client errors out with message:

No RemotePlace found in configuration file

IMHO it would be nice to close the feature gap of the client for local usage by either use the locally defined resources directly for some of it's commands like io, or console, or start coordinator&exporter on-demand internally in some way.