S1 OSV download from ASF

[johntruckenbrodt]

Just as mentioned in #276, adding options for OSV download would be good. Here is another source that can be utilized:
https://s1qc.asf.alaska.edu/

[crivisan]

I found a quick fix to this, but I think they should update the URLs.
Go to: /envs/pyrosar/lib/python3.8/site-packages/pyroSAR/drivers.py
Modify the following argument, in line 1704, to url_options=2
URL is hard coded to option 1 (https://scihub.copernicus.eu/gnss) which is the old website. Option 2 (https://step.esa.int/auxdata/orbits/Sentinel-1) still works for downloading Orbit files.

[johntruckenbrodt]

Thanks @crivisan. Your suggestion has already been implemented in #275 and included in the latest version 0.23.0. This issue is about adding the ASF page as alternative.