decoding not operational with new setup

[tomeichlersmith]

pfdecoder silently ignores all of the data packets since they have a different header word 0xbeef2025.

Additionally, the HGCROCv3b output data packets are a slightly different schema than the v2 data packets pfdecoder and the other decoding classes were used to. We will want to update that as well.

[tomeichlersmith]

The output of the HGCROC is pretty well understood (the HGCROC Manual Working Document is copied to pflib's documentation website: https://ldmx-software.github.io/pflib/HGCROC3b_Working_Document_v1.1.pdf) and that is where I am starting. Relative to the decoding that was in v2 pflib, the HGCROC has been changed from v2 to v3 which is the main alteration to the HGCROC's output data format.

Moreover, we will want to decode the intermediate HGCROC data format because the more complicated ECON output format will need to be emulated #94 in order to avoid having to juggle different custom formats between test benches and the real detector.