Protect the muon decoding from unexpected data

Currently the decoding throws exceptions when a raw bank doesn't look as expected. These are replaced with error counters, and processing of the rest of the raw banks continues.

In addition, some assumptions (that seem to be violated with the current data) are now checked, preventing SIGABRT (invalid subspan arguments).

Adresses #242 but there are most certainly more issues as infrequent SIGABRT happens still in the MuonMon task.

/cc @samarian @mstahl