New schema for the GeoModel SQLite database and updated I/O

==> NOTE: This is a follow-up MR of !317 (closed).

I had to rebase the branch used in !317 (closed) onto main to fix errors raised in the rebase step of the Athena build. But that caused a deep rewrite of the commit history of the original development branch. To avoid affecting the original branch and to remove unnecessary clutter, I renamed the rebased branch and opened a new MR. So, we can test the new rebased branch in the Athena build without modifying the original development branch.

For all details and changes, see the description and the comments of !317 (closed).

Cc: @tsulaia and @boudreau

GeoModelCore/GeoModelHelpers/GeoModelHelpers/StringUtils.h

@@ -28,6 +28,8 @@ namespace GeoStrUtils{
     /// @return 
     std::string resolveEnviromentVariables(const std::string_view str);
 
+    std::string getEnvVar(const std::string_view key);
+
     /// @brief returns the longest substring that's common between the
     ///        two given strings starting from character 0
     std::string_view longestCommonString(const std::string_view firstStr,
@@ -61,6 +63,10 @@ namespace GeoStrUtils{
     template <class ObjType> std::string chainUp(const std::vector<ObjType>& vector,
                                                  const std::string_view glue =";");
 
+    /// Function to set the precision of the conversion from double to string
+    std::string to_string_with_precision(const double a_value, const unsigned n = 16);
+
+    void printStdVectorStrings(const std::vector<std::string> vec);
 }
 #include "GeoModelHelpers/StringUtils.icc"
 #endif
\ No newline at end of file