add isolation WP for muon selection, rename el_iso_wp and mu_iso_wp to reflect they define IDs

For muons, the ID does not include an isolation criterion, this has to be applied separately. As of now in HiggsDNA, we have variable names el_iso_wp and mu_iso_wp although they refer to the IDs. I propose to rename those to ..._id_wpand to include another variable defining the muon isolation WP.