jFEX monitoring update, solving ATR-27831 and ATLASRECTS-7662

This MR is solving few monitoring issues described in:

• ATLASRECTS-7662 - Memory degradation in RAWtoALL
• ATR-27831 - JfexInputMonAlg accessing nonexistent item jtowerEtMeV

It also adds a generic jFEX plot to spot global errors.

setting urgent flag since it makes express reconstruction crash