Implements support for gas lift optimization.

Implements gas lift optimization for a single StandardWell. Support for
gas lift optimization for multi-segment wells, groups of wells and
networks is not implemented yet.

The keywords LIFTOPT, WLIFTOPT, and VFPPROD are used to supply parameters for
the optimization. Also adds support for summary output of liftgas
injection rate via keyword WGLIR.

opm/simulators/wells/WellInterface.hpp

@@ -26,6 +26,7 @@
 
 #include <opm/common/OpmLog/OpmLog.hpp>
 #include <opm/common/ErrorMacros.hpp>
+#include <opm/common/Exceptions.hpp>
 
 #include <opm/parser/eclipse/EclipseState/Schedule/Well/Well.hpp>
 #include <opm/parser/eclipse/EclipseState/Schedule/Well/WellTestState.hpp>
@@ -167,6 +168,12 @@ namespace Opm
                                     Opm::DeferredLogger& deferred_logger
                                     ) = 0;
 
+        virtual void maybeDoGasLiftOptimization (
+            const WellState& well_state,
+            const Simulator& ebosSimulator,
+            DeferredLogger& deferred_logger
+        ) const = 0;
+
         void updateWellTestState(const WellState& well_state,
                                  const double& simulationTime,
                                  const bool& writeMessageToOPMLog,