ENH: IOobjectOption isAnyRead() for checking against NO_READ

- encompasses isReadOptional or isReadRequired check

STYLE: allow LAZY_READ as a shorter synonym for READ_IF_PRESENT

- add helper for downgrading MUST_READ... to LAZY_READ

src/parallel/reconstruct/faReconstruct/faMeshReconstructor.C

@@ -568,7 +568,7 @@ Foam::faMeshReconstructor::faMeshReconstructor
     // Use 'headerClassName' for checking
     bool fileOk
     (
-        (fvFaceProcAddr.readOpt() != IOobjectOption::NO_READ)
+        fvFaceProcAddr.isAnyRead()
      && fvFaceProcAddr.isHeaderClass<labelIOList>()
     );