ICSHWI-8457

Note that this MR includes also !17 (merged) (and should thus be seen as an option to that - i.e. both should not be merged).

Relevant code-changes:

• .h-files renamed to .hpp
• use of pragma once instead of header-guards
• all files have been auto-formatted
  • with EOF-fixer and trailing-whitespace-fixer for all files
  • with black and isort for python
  • with clang-format for C/C++
• the scaling*-files have been somewhat modified; types are auto-deduced and more narrowly scoped or more proximally defined
  • use of auto for types to avoid a bit of what seemed like implicit casting
  • use of size_t for container sizes

Since basically all files have been touched, I'd recommend looking first at the config files /.*, and then at the scaling*.[ch]* files.