Modernize C++ sources using clang-tidy

[jcfr]

Is your feature request related to a problem? Please describe.

Following the update of the minimum C++ version required to build Slicer (now C++17¹), existing code can be improved to use simpler and more modern construct now built-in the c++ languages.

Describe the solution you'd like

The modernize- checks offered by clang-tidy² should be selectively applied to update the sources and then systematically executed through a pre-commit hook.

Describe alternatives you've considered

NA

Additional context

Footnotes

1. https://github.com/Slicer/Slicer/pull/6237 ↩

2. https://clang.llvm.org/extra/clang-tidy/checks/list.html ↩