Add TupleType class

theodolite-benchmarks/flink-commons/src/main/java/theodolite/commons/flink/TupleType.java

+package theodolite.commons.flink;
+
+import org.apache.flink.api.common.typeinfo.TypeInformation;
+import org.apache.flink.api.common.typeinfo.Types;
+import org.apache.flink.api.java.tuple.Tuple;
+import org.apache.flink.api.java.tuple.Tuple2;
+
+/**
+ * Helper methods for creating {@link TypeInformation} for {@link Tuple}s. In contrast to
+ * {@code Types#TUPLE(TypeInformation...)}, these methods bring real type safety.
+ */
+public final class TupleType {
+
+  private TupleType() {}
+
+  public static <T1, T2> TypeInformation<Tuple2<T1, T2>> of(// NOPMD
+      final TypeInformation<T1> t0,
+      final TypeInformation<T2> t1) {
+    return Types.TUPLE(t0, t1);
+  }
+
+}