support filter on RelativeOrbitNumber in burst extractor

[jdries]

When extracting multiple bursts, users usually want to limit to a specific relative orbit, because interferometry algorithms do not really support combining data from different orbits (as far as I understand).

We'd like to add this support to:
https://github.com/eu-cdse/utilities/blob/main/sentinel1_burst_extractor_spatiotemporal.sh