UTC vs. TAI

[nbuffon]

Problem

• UTC is x seconds delayed from TAI where x is not a constant
• x can be known through existing database being updated at 6 month interval
• GNSS time is 19 seconds behind TAI

Solutions

1. Publish the leap second count (x) through the .../info topic

[ymorin-orange]

Note: in english, International Atomic Time is still abbreviated TAI, from its French name temps atomique international (Wee! 😄). I've updated the issue description accordingly.

[ymorin-orange]

FTR: the up-to-date list of leap-seconds is available on-line at: https://data.iana.org/time-zones/data/leap-seconds.list