align Plane metadata with IVOA Radio IG work on an ObsCore extention for radio

[pdowler]

add
Observation.telescope.trackingMode : vocabulary

Plane.position.minBounds : shape
Plane.position.maxAngularScale : interval -- min/max scale
Plane.energy.resolution : double -- absolute resolution
Plane.energy.resolutionBounds : interval -- min/max abs res.
Plane.time.exposureBounds : interval -- min/max exposure time

Plane.uv : Visibility
distance : interval -- min/max
distributionEccentricity : double
distributionFill : double

** maybe add**
Plane.position.energyDependent : boolean -- range of shape, resolution, and scale is energy dependent