Support satposXYZ from SARDEMProjection in ComputeLIA

Current version of ComputeLIA takes sensor position from the orbit metadata, this works well given the result image is produced in S1 SAR geometry, and for each line, we know the associated azimuth time.

In order to support output in any other geometry, we need to consume sensor positions from another file: the one produced by SARDEMProjection.