Draft: [trigEGam] Integration beteween mongroups and TrigEgammaMonitoring

This MR is to include mongroups inside the TrigEgammaMonitoring framework.

• A method was implemented in the TrigEgammaMonitCategoryMT reading, for now, the mongoups from JSON local file produced by a ART test.
• At this moment, only the primary chains was configured, and then, called inside the TrigEgammaMonitorConfigMT.py file .
• In a next MR, we will include a logic to route chains to shifter and expert folders automatically, according to their respective mongroups.

JIRA Ticket: ATR-25841 .

ping: @safarzad , @cjmeyer , @fernando , @kyjones and @jlieberm

Tracking/TrkDetDescr/TrkVolumes/src/Volume.cxx

@@ -78,13 +78,13 @@ Trk::Volume::clone() const
   return new Trk::Volume(*this);
 }
 
-#if defined(FLATTEN) && defined(__GNUC__)
+#if defined(__GNUC__)
 // We compile this package with optimization, even in debug builds; otherwise,
 // the heavy use of Eigen makes it too slow.  However, from here we may call
 // to out-of-line Eigen code that is linked from other DSOs; in that case,
 // it would not be optimized.  Avoid this by forcing all Eigen code
 // to be inlined here if possible.
-__attribute__((flatten))
+[[gnu::flatten]]
 #endif
 bool
 Trk::Volume::inside(const Amg::Vector3D& gp, double tol) const