Make c/c++ interface private

[sondreso]

We will make the c/c++ interface of resdata (formerly known as ecl/libecl) private.

The rationale is that there are a lot of functionality that is only exposed in c/c++ which is in little use, and we would like to clean this up in order to have a library that is easier to maintain. ert used to be a big consumer of this interface, but this is not the case anymore. Other users

The next step is ta create a new major version bump of Resdata with the c/c++ interface as private. This means all comments in README and documentation about the c/c++ interface will disappear. Also the following lines will be removed:

resdata/python/resdata/__init__.py

Line 69 in c62737a

return ctypes.CDLL(path, ctypes.RTLD_GLOBAL)

resdata/setup.py

Line 86 in c62737a

"-DCMAKE_INSTALL_INCLUDEDIR=python/resdata/.include",

Note: The binaries exposed by resdata is still considered public:

resdata/setup.py

Lines 37 to 53 in c62737a

	"CF_dump",
	"convert.x",
	"rd_pack.x",
	"rd_unpack.x",
	"grdecl_grid",
	"grdecl_test.x",
	"grid_dump.x",
	"grid_dump_ascii.x",
	"grid_info.x",
	"kw_extract",
	"kw_list.x",
	"load_test.x",
	"make_grid",
	"ri_well_test",
	"segment_info",
	"select_test.x",
	"summary.x",