User configurable Electron-electron OR configuration option added

Made the electron-electron OR a configurable option in SUSYTools. Some changes to the default SUSYTools config file (changing to p-flow jets by default for example, updating the jet uncertainties to use the combination ready set of JES uncertainties). Added the 3G combinations config file.

The changes to the default config file will require me to push new references to cvmfs, which I'll do shortly (the CI will fail due to the changes otherwise).

These references have now been pushed, so the SUSYTools tests in the CI will fail for other MRs, until this MR is merged.

Tagging @salderwe , @cmerlass (for the config file) and @oducu (for the configurable elel-OR).

Cheers

John