INIT File: Add Writer Based on OutputStream::Init

This commit adds a new facility for creating the simulation runs'
INIT file.  This is intended to replace the implementation of class
EclipseIO::Impl's writeINITFile.  Initial structure taken from
current implementation of EclipseIO::Impl::writeINITFile().

opm/output/eclipse/WriteInit.hpp

@@ -0,0 +1,60 @@
+/*
+  Copyright (c) 2019 Equinor ASA
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef OPM_WRITE_INIT_HPP
+#define OPM_WRITE_INIT_HPP
+
+#include <map>
+#include <string>
+#include <vector>
+
+namespace Opm {
+
+    class EclipseGrid;
+    class EclipseState;
+    class NNC;
+    class Schedule;
+
+} // namespace Opm
+
+namespace Opm { namespace data {
+
+    class Solution;
+
+}} // namespace Opm::data
+
+namespace Opm { namespace EclIO { namespace OutputStream {
+
+    class Init;
+
+}}} // namespace Opm::EclIO::OutputStream
+
+namespace Opm { namespace InitIO {
+
+    void write(const ::Opm::EclipseState&              es,
+               const ::Opm::EclipseGrid&               grid,
+               const ::Opm::Schedule&                  schedule,
+               const ::Opm::data::Solution&            simProps,
+               std::map<std::string, std::vector<int>> int_data,
+               const ::Opm::NNC&                       nnc,
+               ::Opm::EclIO::OutputStream::Init&       initFile);
+
+}} // namespace Opm::InitIO
+
+#endif // OPM_WRITE_INIT_HPP