New cpp folder structure

Signed-off-by: Alexander Borsuk <me@alex.bio>

libs/indexer/data_source_helpers.hpp

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "geometry/point2d.hpp"
+
+#include <functional>
+
+class DataSource;
+class FeatureType;
+
+namespace indexer
+{
+void ForEachFeatureAtPoint(DataSource const & dataSource, std::function<void(FeatureType &)> && fn,
+                           m2::PointD const & mercator, double toleranceInMeters = 0.0);
+}