Determine which AUTOSAR / MISRA C++ to apply

In #123, AUTOSAR compliance was raised. From the standpoint of this project, no specific standard has been applied so far. However, we may be asked to provide some sort of compliance in the future.

AUTOSAR is the previous standard that would be used in automotive standards. The last update was several years ago for C++14.

MISRA C++ 2023 is the latest MISRA C++ standard, and has superseded AUTOSAR (the standards were merged). It covers both C++17 and C++20.

It seems to me the best choice would be to pick MISRA C++ 2023 if we are going to add this requirement. It would be most compatible with the work we are currently doing (which is in C++17), and would allow for us to move to C++20 should we decide to (see #109).