HB radiation damage model

This commit introduces a radiation damage model for HB, based on a very rough extrapolation from the HE radiation damage model (as described in the comments of HBDarkening.cc). The associated recalibration is also introduced, using the same method as HE. The implementation includes a "scenario" parameter like the one recently introduced for HEDarkening, to allow for easy addition of HB scintillator replacement scenarios in the future. HB darkening currently is *not* turned on by default, but must be activated by manually adding set_HB_aging_scenario to the config file. (This may be changed in the near future).

This commit also fixes a small bug introduced in #3207 which assigned the wrong depth segmentation to towers 16 and 17 when calculating the HE recalibration. The effect of this bug on aging simulations would have been negligible.
I think this line is causing very bizarre crashes in several workflows.  Gen-Sim is crashing right at the end of the job, I'd post the stacktrace but I think it's irrelevant.
Since *m_HBDarkening* is not set to zero at the start, if *ageingFlagHB* is not used then this will delete a random section of memory.
I have a fix ready, I'll test and then put in a new pull request.