Filter out spurious gps points

[cyberorg]

Many tracks show pilots teleporting far away and back, those points needs to be discarded.

Suggestions from chatgpt for nodejs libraries that can be used:

1. If you want a pre-built solution, the gps-filter library is specifically designed for filtering out invalid or noisy GPS data.

2. For more control, you can use gps-utils or geolib to calculate distances and speeds and apply your own filtering logic based on your requirements.

The second option can be used to calculate distance between current and last position and if it is greater than possible to achieve on speeds at last few positions then they can be discarded.