some latitude/longitude hardcoded in sites.json not accurate

### Description

For the coordinates of the Mauna Kea observatories, I found inconsistencies between sites.json and IRTF reports.
https://irtfweb.ifa.hawaii.edu/observing/telescopeCoordinates.php
At least the IRTF one is consistent with Subaru; https://subarutelescope.org/Observing/Telescope/Parameters/

### Additional context

I need accurate latitude and longitude to calculate precession-corrected parameters.