Cleanup documentation and interface of the LDPC segment coding libraries
Fix interface: The LDPC segment decoder interface had variables
'harq_pid', 'ulsch_id' and 'C' that are not useful to the segment
decoder. This MR removes these variables from the interface.
Fix documentation: libconfig log do not display anymore by default so we
may better not show them in the documentation to avoid any
misunderstanding.
Remove ldpc_cl library since the library does not work.