STYLE: consistent lookupOrDefault template parameters

- in many cases can just use lookupOrDefault("key", bool) instead of
  lookupOrDefault<bool> or lookupOrDefault<Switch> since reading a
  bool from an Istream uses the Switch(Istream&) anyhow

STYLE: relocated Switch string names into file-local scope

src/functionObjects/solvers/scalarTransport/scalarTransport.C

@@ -209,7 +209,7 @@ Foam::functionObjects::scalarTransport::scalarTransport
     resetOnStartUp_(false),
     schemesField_("unknown-schemesField"),
     fvOptions_(mesh_),
-    bounded01_(dict.lookupOrDefault<Switch>("bounded01", true))
+    bounded01_(dict.lookupOrDefault("bounded01", true))
 {
     read(dict);