MEDIUM: config: move the "bind" TCP parameters to proto_tcp

MEDIUM: config: move the "bind" TCP parameters to proto_tcp

Now proto_tcp.c is responsible for the 4 settings it handles :
  - defer-accept
  - interface
  - mss
  - transparent

These ones do not need to be handled in cfgparse anymore. If support for a
setting is disabled by a missing build option, then cfgparse correctly
reports :

  [ALERT] 255/232700 (2701) : parsing [echo.cfg:114] : 'bind' : 'transparent' option is not implemented in this version (check build options).