Serve local time as NTP server

**Describe the problem you have/What new integration you would like**

I like to have the possibility to serve the time gathered by the gps component. For example as a ntp server.

**Please describe your use case for this integration and alternatives you've tried:**

I need to have a valid time source for an offline environment.

As all esp and even raspberries lacking a rtc it would be great to use the (already supported) time source from gps which should have good accuracy (stratum 1) and should be even better than classical rtc's for time keeping.

**Additional context**

https://github.com/liebman/ESPNTPServer
https://hackaday.io/project/28013-esp-gps-ntp-server