Add an auto-detect model mode to local_dc for cymac support

Cymacs and test stands do not necessarily have a stable set of models. So it would be a good idea to have an auto-detect mode on the local_dc.

• periodically scans for '_daq' mbufs
• adds new entries to the concentrated output
• removes entries where it is the only one holding it open
• automatically detects iop to use as the 'fast' clock to read first