[FEATURE] Modify the causality of the GT example so that it matches our current standards

[helenev-met]

What is not your precise need ?

Today :

• TET is mentioned : so it is not a BC (either an input) -> it should be a BC
• combustionChamber_eta is a parameter and is given a value -> should be an output calibrated by Q_gaz
• Q_gaz in identified as a BC -> should be an input for calibration
• Compressor outlet pressure is an input for calibration -> it should be a BC
• And we should Identify that the turbine_expansion_rate remains free
• Replace the enthalpy inputs by temperature inputs
  And it would be great to include sensors also for BC. But it's not a priority compared to the causality update👍