New ringer low et tuning files
This MR is related to Ringer migration (ART-20143).
The main change is the ringer selector files to be used in TrigEgammaFastCaloHypoTool.
The new files are TrigL2_20201018_r3, the suffix r3 indicates the third release of Ringer which contains the models for ET higher, and below 15 GeV.