added directory with xml files for electron channel

as requested by Roman, i uploaded my config files for the electron channel for the nominal analysis and the systematics

* these config files are 'electron channel' specific (some options must be different for the muon channel)
* i left the paths that i used to run the production (one of course should customize them if necessary)
* the W+jets scale/matching samples (with latest lumis) are configured in the _W*flavor_ files, where flavor splitting is applied