Allow setting for accuracy when saving track

[JensKoopmann]

Since the accuracy of the gps position is already displayed, it would be great to also use it to avoid inaccurate data in the track

[vincentneo]

I assume this is a duplicate of #155?

[JensKoopmann]

Not exactly. My suggestion is not to save to information since it would not be a standard gpx field but to only save points with an sufficient accuracy that can be set by the user