ATLASG-1635: CA track iso in derivation
This is trying to migrate custom track isolation computations in derivation to CA style, following https://its.cern.ch/jira/browse/ATLASG-1635
In the old style, there are lots of variables computed for muons. For the time being, only the ones needed (from CP content) are computed. Also, for photons, no new variable is needed principle (to be checked with WP kept in IsolationSelection)
tagging @jcatmore
Edited by Jean-Baptiste De Vivie De Regie