fvConstraints: Added limitPressure which replaces pressureControl.limit

To provide more flexibility, extensibility, run-time modifiability and
consistency the handling of optional pressure limits has been moved from
pressureControl (settings in system/fvSolution) to the new limitPressure
fvConstraint (settings in system/fvConstraints).

All tutorials have been updated which provides guidance when upgrading cases but
also helpful error messages are generated for cases using the old settings
providing specific details as to how the case should be updated, e.g. for the
tutorials/compressible/rhoSimpleFoam/squareBend case which has the pressure
limit specification:

SIMPLE
{
...
    pMinFactor      0.1;
    pMaxFactor      2;
...

generates the error message

--> FOAM FATAL IO ERROR:
Pressure limits should now be specified in fvConstraints:

limitp
{
    type       limitPressure;

    minFactor  0.1;
    maxFactor  2;
}

file: /home/dm2/henry/OpenFOAM/OpenFOAM-dev/tutorials/compressible/rhoSimpleFoam/squareBend/system/fvSolution/SIMPLE from line 41 to line 54.

tutorials/multiphase/multiphaseEulerFoam/RAS/bubblePipe/system/fvConstraints

@@ -0,0 +1,24 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     | Website:  https://openfoam.org
+    \\  /    A nd           | Version:  dev
+     \\/     M anipulation  |
+\*---------------------------------------------------------------------------*/
+FoamFile
+{
+    version     2.0;
+    format      ascii;
+    class       dictionary;
+    object      fvConstraints;
+}
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+limitp
+{
+    type       limitPressure;
+
+    min        1e4;
+}
+
+// ************************************************************************* //

tutorials/multiphase/multiphaseEulerFoam/RAS/bubblePipe/system/fvSolution

@@ -73,7 +73,6 @@ PIMPLE
 
     faceMomentum        true;
 
-    pMin                1e4;
 }
 
 relaxationFactors