jFEX MET and SumET EDM update

This MR is meant to harmonise the jFEX MET and SumEt in the same way as the other jFEX EDMs (such as jTau, jJ and jLJ).

• Some variables have been removed
• Some functions have been renamed or removed
• The variables now saved in the Aux container are filled correctly
• Additionally I added two more variables in the MET EDM
  • Ex() and Ey() where they return the Et in 1 MeV scale
• Also I added two more variables in the SumEt EDM
  • Et_lower() and Et_upper() where they return the Et_lower/upper in 1 MeV scale

Since the L1Topo is already using our MET EDM, I needed to modify also their variables.