ENH: Added fieldMinMax function object default config

etc/caseDicts/postProcessing/fields/fieldMinMax

+/*--------------------------------*- C++ -*----------------------------------*\
+  =========                 |
+  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
+   \\    /   O peration     |
+    \\  /    A nd           | Web:      www.OpenFOAM.com
+     \\/     M anipulation  |
+-------------------------------------------------------------------------------
+Description
+    Calculates the mimima and maxima of fields
+
+\*---------------------------------------------------------------------------*/
+
+type            fieldMinMax;
+libs            ("libfieldFunctionObjects.so");
+
+fields          (".*");
+
+executeControl  timeStep;
+
+// ************************************************************************* //