Chase Group/Node Summary API Update

This is in preparation of adding support for outputting the network
node pressure quantity, GPR, to the summary file.  In particular,
'GroupValues' is renamed to 'GroupAndNetworkValues' and has new
individual datamembers for the former group-level data and the new
node-level data.

Update BlackoilWellModel::groupData() and CollectToIORank
accordingly and bring the parallel restart facility in line with the
new layout.

tests/test_ParallelRestart.cpp

@@ -250,6 +250,13 @@ Opm::data::GroupData getGroupData()
         getGroupGuideRates()
     };
 }
+
+Opm::data::NodeData getNodeData()
+{
+    return Opm::data::NodeData {
+        123.457
+    };
+}
 }
 
 
@@ -385,6 +392,14 @@ BOOST_AUTO_TEST_CASE(dataGroupData)
     DO_CHECKS(data::GroupData)
 }
 
+BOOST_AUTO_TEST_CASE(dataNodeData)
+{
+    const auto val1 = getNodeData();
+    const auto val2 = PackUnpack(val1);
+
+    DO_CHECKS(data::NodeData)
+}
+
 BOOST_AUTO_TEST_CASE(CellData)
 {
     Opm::data::CellData val1;
@@ -409,12 +424,17 @@ BOOST_AUTO_TEST_CASE(RestartValue)
     auto wells1 = Opm::data::WellRates {{
         { "test_well", getWell() },
     }};
-    auto groups1 = Opm::data::GroupValues {{
-        { "test_group1", getGroupData() },
-    }};
+    auto grp_nwrk_1 = Opm::data::GroupAndNetworkValues {
+        {                       // .groupData
+            { "test_group1", getGroupData() },
+        },
+        {                       // .nodeData
+            { "test_node1", getNodeData() },
+        }
+    };
 
     const auto val1 = Opm::RestartValue {
-        getSolution(), std::move(wells1), std::move(groups1)
+        getSolution(), std::move(wells1), std::move(grp_nwrk_1)
     };
     const auto val2 = PackUnpack(val1);