AnalysisTop: Adding preliminary support for electron PLIV SFs

E/gamma has recently released official PLIV isolation scale factors. This change will make them available for analyses in AnalysisTop.

The user can specify the required WP (PLImprovedTight or PLImprovedVeryTight) as options for ElectronIsolation and ElectronIsolationLoose in the cut file. This isolation is only available for TightLH and MediumLH identification and AnalysisTop will crash with a corresponding error message, if other ID WPs are used. It will also crash if the input samples are AFII, as the PLIV SFs are only valid for FS. Since PLIV is not yet available for online isolation, a warning is printed that the trigger doesn't exactly match the offline isolation. ECIDS can be used by setting UseElectronChargeIDSelection to True in the cut file.