Add overlap removal option to reject electrons in DR cones of muons

The IFF has seen for a while that the overlap removal doesn't remove all electrons in the close vicinity of muons (see here). Previously, the tool only removed electrons that shared a track with a muon. But the electrons didn't have a track associated with them and consequently were not removed. (Don't ask me why these objects are reconstructed as electrons. In MC, they seem to come from photons.)

The IFF has requested in a jira ticket that an additional deltaR based overlap removal be added between electrons and muons. This is implemented in this MR. It is deactivated by default and can be activated with the property UseDRMatching on the EleMuSharedTrkOverlapTool.