ENH: use static to define default blockMesh verbosity

- make handling of verbosity more consistent.

  Make all setter return the old value, remove (unused) default
  parameter as being counter-intuitive.  This makes it easier to
  restore the original values.

  For example,

     const bool oldVerbose = sampler.verbose(false);
     ...
     sampler.verbose(oldVerbose);

src/randomProcesses/noise/noiseModels/surfaceNoise/surfaceNoise.C

@@ -456,7 +456,7 @@ bool surfaceNoise::read(const dictionary& dict)
         );
 
         // Use outputDir/TIME/surface-name
-        writerPtr_->useTimeDir() = true;
+        writerPtr_->useTimeDir(true);
 
         return true;
     }