Switch jFEX jet calibration to eta binning instead of ET binning

The ET (or pT) binned calibration of jFEX smallR jets was never really used other than a flat factor per jFEX module (thus giving some limited eta granularity already). The main reason for this are odd jumps in the ET spectrum that would be introduced when using such ET binned calibration factors (jets below some bin edge could "overtake" jets originally just above the bin edge).

As such a binned calibration is already available in firmware this is intended to be switched to be binned as a function of the (per-FPGA) eta coordinate (related FW MR: https://gitlab.cern.ch/atlas-l1calo/jfex/jfex_firmware/-/merge_requests/183) which shows significant potential to further improve the turn-on sharpness for L1 jet triggers. This MR here adapts the simulation accordingly.

Ideally there'd be a switch between ET and eta based calibration, possibly depending on the year/period/... . In practice jFEX has not been actively used for physics data taking up until now, so even a hard switch to eta based calibration should still be acceptable.