The argument characterizes the direction the layer is added - either on top or on bottom.

Use directly addLayerToMesh.

The fmt library happily accepts std::string without
any conversions.

Only in ERR/WARN/INFO/DBUG/OGS_FATAL and similar, not in
formatted output like xml files.

Now includes the copyright message and the version info with git hash.

New versions of logog do not have an implicit ; after the macros.

Clang format run on near-the-header lines.

Happy New Year

FileIO -> MeshLib::IO.

In order to make OGS more modular:
- The {read/write}Mesh{From/To}File.{h,cpp} are moved from FileIO to MeshLib/IO.
- The FileIO/Legacy folder was moved to MeshLib/IO/Legacy.
- Include paths are changed according the changes above.