monitor/ll: Add support for connection parameter command.

monitor/ll: Add support for connection parameter command.

LL_CONNECTION_PARAM_REQ (0x0f)
  Interval min: 7.50 msec (0x0006)
  Interval max: 7.50 msec (0x0006)
  Latency: 0 (0x0000)
  Timeout: 5000 msec (0x01f4)
  Preffered periodicity: 0.00 (0x00)
  Reference connection event count: 4 (0x04)
  Offset 0: 0.00 msec (0x00)
  Offset 1: 0.00 msec (0x00)
  Offset 2: 1.25 msec (0x01)
  Offset 3: 0.00 msec (0x00)
  Offset 4: 2.50 msec (0x02)
  Offset 5: 0.00 msec (0x00)

LL_CONNECTION_PARAM_RSP (0x10)
  Interval min: 7.50 msec (0x0006)
  Interval max: 7.50 msec (0x0006)
  Latency: 0 (0x0000)
  Timeout: 5000 msec (0x01f4)
  Preffered periodicity: 0.00 (0x00)
  Reference connection event count: 4 (0x04)
  Offset 0: 318.75 msec (0xff)
  Offset 1: 318.75 msec (0xff)
  Offset 2: 318.75 msec (0xff)
  Offset 3: 318.75 msec (0xff)
  Offset 4: 318.75 msec (0xff)
  Offset 5: 318.75 msec (0xff)