Add client and server port logging

I have added both client and server port numbers as we can see them both being useful in some cases. You will see the functions to obtain port numbers are performed on every call to write_accesslog. It would be less overhead to perform this in the constructor and store as private member variables - if you prefer that I will update the code.
high_resolution_clock::now is called in this function several time.
To reduce syscall, it would be better to allocate another member in LogSpec struct and assign current time on call site.