Add NTPServerSync() function to sync datetime with NTP server.

Only for modules that buffer the data internally

For loggers that return data "immediately" (unbuffered, data sent w/o request) read will "maintain" and look for any incoming data as long as the socket is open.  Use timedRead if you want a timeout.

For modems that buffer the response and wait for you to request data, read will stop if socket closes OR if there is no longer any data in the modem's response buffer.