COM: Separate htc FO from general FO and reactingEuler solvers (#1714)

The phase systems tables for multiphase solvers create conflict
between each other as they are defined in the same namespace and using
similar class names.

Therefore a special htc function object for reactingEulerSolver was
added (reactingEulerHtcModel), located under
src/phaseSystemModels/reactingEulerFoam/functionObjects/

This commit includes the following:

- Relocate solvers/reactingEulerFoam functionObjects to
  src/phaseSystemModels
- Remove links for fieldFunctionObject to multiphase libs to avoid
  conflicts
- New FO for htc for reactingEulerFoam called reactingEulerHtcModel

tutorials/heatTransfer/buoyantPimpleFoam/hotRoom/system/controlDict

@@ -49,4 +49,19 @@ adjustTimeStep  no;
 
 maxCo           0.5;
 
+functions
+{
+    htc
+    {
+        type            heatTransferCoeff;
+        libs            (fieldFunctionObjects);
+        field           T;
+        writeControl    outputTime;
+        writeInterval   1;
+        htcModel        fixedReferenceTemperature;
+        patches         (ceiling);
+        TRef            373;
+    }
+}
+
 // ************************************************************************* //

tutorials/heatTransfer/chtMultiRegionTwoPhaseEulerFoam/solidQuenching2D/system/controlDict

@@ -63,8 +63,8 @@ functions
 {
     htc
     {
-        type            heatTransferCoeff;
-        libs            (fieldFunctionObjects);
+        type            reactingEulerHtcModel;
+        libs            (reactingEulerFoamFunctionObjects);
         region          water;
         field           T.liquid;
         writeControl    outputTime;
@@ -94,7 +94,7 @@ functions
 
         operation       areaAverage;
 
-        fields          ( heatTransferCoeff(T.liquid) );
+        fields          ( reactingEulerHtcModel(T.liquid) );
     }
 }