Better search interface

[DinoBektesevic]

Searching as an [min, max[ offset from an average angle of rotation of the image is a bit confusing. Same when searching using speed instead of velocity. The primary reason for this is that in the end this is translated into in-image distances, i.e. into (vx, vy) --> (dx, dy) distances. Which can lead to some confusing scenarios.

The naming scheme is also confusing and feels like much of it should be removed. We have multiple *thresholds but lh_level, avg_ang is not very clear either.

Making this a discussion so that we can record any ideas we might have regarding this.