Remove all references to application specific (ADC, TDC, FD) from code,
in order to generalize the library.

Major changes include:

- removal of application-specific initialisation and channel enabling code
- removal of libwrtd-devices.c
- removal of struct wrtd_mt_config
- addition of fields to wrtd_root in order to be able to dynamicaly
  retrieve information that was previously stored in wrtd_mt_config
- static names and numbering for local channels: local inputs are named
  LC-I<n>, local outputs are named LC-O<n>. Numbering (<n>) starts from
  device 0 of cpu 0 and increases, with a separate counter for inputs
  and outputs.
- rework of source and destination CPU calculation to handle cases where
  multiple CPUs are capable of network RX/TX
- update firmware to reflect the above changes