Modifications to retrieve adc_good information in SBSGEMModule

[efuchey]

Modifications to retrieve "adc_good" information for GEM FT and FPP:

• added "adc_good" branches in gep_tree_digitized class
• read through "adc_good" branches while reading other branches (adc, samp, strip, etc) for detectors gemFT and gemFPP in SBSSimDecoder
• encoding adc_good info in the front 12 bits of the 32 bits data word (i.e. loading from bit 20 to 31 i.e. bitwise << 20) loaded by SBSSimDecoder into the THaEvData object
• retrieving adc_good info for MC inside SBSGEMModule::Decode()
  => in the event adc_good is not zero, it ends up being tangled with strip in THaEvData::GetRawData(...)
  => further decoding to get strip info and adc_good info disentangled (for MC only!);