This merge request follows !54707 (merged) to move and split the merging and overlap removal tools into a new package so that they are usable downstream as well. It is related to a similar MR for muons !55019 (merged). Tested that this compiles against both Athena and AnalysisBase.
LRTElectronAnalysisTools under ElectronPhotonID to collect tools related to LRT electrons
ElectronLRTMergingAlg added that uses the overlap removal tool to merge collections.
ElectronLRTOverlapRemovalTool implements the overlap removal.