prefer settings over pragmas

When implementing configuration options, prefer database settings over pragma functions to maintain consistency and better user experience. Settings provide a unified interface that’s easier to discover, document, and manage compared to scattered pragma functions.

Instead of creating pragma functions like:

set.AddFunction(PragmaFunction::PragmaStatement("enable_logging", PragmaEnableLogging));

Use database settings:

// In settings registration
void EnableLoggingSetting::SetGlobal(DatabaseInstance *db, DBConfig &config, const Value &input) {
    config.options.enable_logging = input.GetValue<bool>();
}

This approach consolidates configuration management, eliminates the need for environment variables scattered throughout the codebase, and provides a consistent SET variable=value interface. When multiple configuration sources exist (environment variables, pragma functions, attach options), refactor them into a unified settings system to reduce complexity and potential conflicts. Consider using table functions (CALL enable_logging(...)) for operations that require parameters or complex logic, but keep simple boolean/value configurations as settings.