Further simplify addConditionDerivation

add an overload which requires explicitly the 'parent' algorithm, as then the parent can be used to get the derivationmanager and query for the output condition key.

This allows eg.

   StatusCode RawToHits::initialize() {
-    auto sc = Transformer::initialize();
-    if ( sc.isSuccess() )
-      addConditionDerivation<ComputeTilePosition( const DeMuonDetector& )>( DeMuonLocation::Default,
-                                                                            inputLocation<2>() );
-    return sc;
+    return Transformer::initialize().andThen( [&]() {
+      addConditionDerivation<ComputeTilePosition( const DeMuonDetector& )>( *this, DeMuonLocation::Default );
+    } );
   }