Transition to C++17 as the minimum standard

I propose that on 2022-07-04T04:00:00Z Slicer transition to set the minimum C++ standard to C++17. See the following pull request for previous discussion and what will be integrated to complete this change.

Visual Studio 2017 (15.7) was announced to officially conform with the C++ standard of C++11, C++14 and C++17