Implement local_dc
Local_dc reads RT model data from mbuf (rmIpcStr) concentrates the data into one block and stores it in an output mbuf (daq_multi_cycle_data_t).
In a standalone system this would be the data concentrator. On a larger system, this prepares data for a streamer process.
This also adds a basic test for local_dc which starts several local simulated FE streams, concentrates their data and checks that each channel is available in the output with the expected values.
This removes fe_data_concentrator. This updates code in fe_stream_test. This adds a new fe_stream_check, renaming the old (and disabled) one to fe_stream_check_nds.
This also enables cmake based testing.
!!Warning the tests fail unless mbuf and gpstime are enabled (ie loaded)!!