code reorganisation & modification in hrc

- Code reorganisation:
  + to have a clearer separation between hrc & decen
  + hrc & decen now have separate stream, task and worker structure
  + they share stream set (manage set of stream descriptor), interface to get communicate with snet-rts and interface to get hardware information

- Modification in hrc:
  + use free pool of stream/stream descriptor to avoid lock. This provide higher performance