gFex Simulation Updates

With this MR, the following changes have been made:

• the gFex simulation has been updated to arrange the forward input as in firmware (changes in gFEXFPGA and gFEXSim tools)
• the gTowerMakerFromGfexTowers tool is introduced to build gTower objects from the readout gTowers, to be used as input to the gFEX simulation and to obtain emulated trigger objects as output (see similar implementation for jFEX !63254 (merged))
• note that if the readout gTowers are not available (but they should be always available in data by default), CaloCell/TriggerTower containers filled with readout SuperCells/Tile towers are used instead;
• the gFexDriver and FexReprocessingRun3 have been updated consequently;
• the conversion from the simulation ID to the firmware ID for the gTowers has been moved into the gTower class.