Load Analytic Aquifer Objects from Restart File

This commit adds support for creating the analytic aquifer objects

    Opm::AquiferCT
    Opm::Aquifetp
    Opm::Aquancon
    Opm::AquiferConfig

from information stored in the restart vectors

    {I,S,X}AAQ
    {I,S}CAQ

We add a new helper class

    Opm::RestartIO::RstAquifer

which contain the same data members as the '*_data' structures of
the analytic aquifer objects.  Those analytic aquifer objects then
get friendship from the '*_data' structures in order to assign the
private members from the corresponding restart information.  We
finally add a gateway to EclipseState that consumes an RstAquifer
instance and overwrites the internal AquiferConfig object when the
restarted run contains analytic aquifers.

Update RstState constructor API to meet requirements of RstAquifer,
notably by adding an EclipseGrid parameter.  That in turn is needed
by the RstAquifer to translate connection (I,J,K) tuples to active
cell IDs.

Note that if an analytic aquifer does not have any connections then
this facility will not load said aquifer.  That may be a problem
when plotting summary curves, but we will address the issue later if
it comes up.

opm/io/eclipse/RestartFileView.hpp

@@ -57,6 +57,8 @@ public:
     getKeyword(const std::string& vector, const int occurrence = 0) const;
 
     const std::vector<int>& intehead() const;
+    const std::vector<bool>& logihead() const;
+    const std::vector<double>& doubhead() const;
 
 private:
     class Implementation;