GeometricField: Renamed internalField() -> primitiveField() and dimensionedInternalField() -> internalField()

These new names are more consistent and logical because:

primitiveField():
primitiveFieldRef():
    Provides low-level access to the Field<Type> (primitive field)
    without dimension or mesh-consistency checking.  This should only be
    used in the low-level functions where dimensional consistency is
    ensured by careful programming and computational efficiency is
    paramount.

internalField():
internalFieldRef():
    Provides access to the DimensionedField<Type, GeoMesh> of values on
    the internal mesh-type for which the GeometricField is defined and
    supports dimension and checking and mesh-consistency checking.

src/dynamicFvMesh/dynamicRefineFvMesh/dynamicRefineFvMesh.C

@@ -344,7 +344,7 @@ Foam::dynamicRefineFvMesh::refine
 
                 surfaceScalarField& phi = *iter();
 
-                sigFpe::fillNan(phi.internalFieldRef());
+                sigFpe::fillNan(phi.primitiveFieldRef());
 
                 continue;
             }

src/dynamicFvMesh/include/meshCourantNo.H

@@ -36,7 +36,7 @@ if (mesh.nInternalFaces())
 {
     scalarField sumPhi
     (
-        fvc::surfaceSum(mag(mesh.phi()))().internalField()
+        fvc::surfaceSum(mag(mesh.phi()))().primitiveField()
     );
 
     meshCoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();