Use only C-locale functions wxString::ToCDouble and fmt::format{}
functions so that we do not need to set the locale for file io
operations
This also introduces a cmake check that looks for certain banned
functions (strtod, strtof and atof) that convert strings into doubles
by the user locale or formatting specifiers like %f/%g that convert
doubles into strings by the users locale. It will prevent compilation
in this case.
For the limited cases where we want to show the user a string in their
locale, we have an override string "format:allow" that can be added to
lines in order to allow them with %f/%g format specifiers
