Task #1871: RSP image BP v9.3 and AP v9.3 with subband data output (SDO) for Aartfaac.

- default after power up the SDO packet output is off, to allow this image to be used on foreign stations with 24 RSP (for which otherwise the RAD latency becomes just too big for the Rx FIFOs if also subbands need to be transported next to the beamlets and crosslets)
- the subbands are requantized by truncating the MSbits (= wrapping) and by rounding the LSbits:
  16 bit --> keep all LSbits so subband re, im [17:0] --> [15:0]
   8 bit --> round 2 LSbit   so subband re, im [17:0] -->  [9:2]
   5 bit --> round 2 LSbit   so subband re, im [17:0] -->  [6:2]
   4 bit --> round 3 LSbit   so subband re, im [17:0] -->  [6:3]