Improving the default values for object selectors

In this MR we aim at normalising the options set for various objects:

• the eta boundaries of the EM calorimeter for electrons and photons ;
• the maximal eta for muons ;
• a structure for the photon selector that mimics the electron one ;
• the various triming and pt sorting ;
• Using Gaudi properties as advertised here

That would help to highlight when different parameters are set.