Updates to eFEX monitoring histos to allow any (x)ToBs from configurable list

Modified EfexMonitorAlgorithm.<cxx/h/py> to allow configurable list of ToBs to be monitored using ReadHandleKeyArray (@lubaines ). Further updates to separate histogram booking to be after ToB selection, to prevent fatal errors (@thompson ). Also updated LVL1CaloMonitoringConfig.py to include these changes for validation.