STYLE: use getOrDefault instead of lookupOrDefault

- now mark methods with strict deprecation, to make it easier to find
  their use but without adding extra compilation noise for others

ENH: minor update for Enum methods and iterator

- add warnOnly (failsafe) option for readEntry and getOrDefault

- add good() method to Enum iterator (simliar to HashTable)

- replace unused/fragile Enum find() methods with iterator return
  that can be used more generally

src/regionFaModels/functionObjects/setTimeStep/setTimeStepFaRegionsFunctionObject.C

@@ -96,7 +96,7 @@ bool Foam::functionObjects::setTimeStepFaRegionsFunctionObject::read
     if (timeFunctionObject::read(dict))
     {
         // Ensure that adjustTimeStep is active
-        if (!time_.controlDict().lookupOrDefault<bool>("adjustTimeStep", false))
+        if (!time_.controlDict().getOrDefault<bool>("adjustTimeStep", false))
         {
             FatalIOErrorInFunction(dict)
                 << "Need to set 'adjustTimeStep' true to allow timestep control"