vectorize astroquery.esa.hsa & HSA.download_data

I would like to query the Herschel archive for ~thousands of spectra based on position (maybe a million one day??). Right now I have skycoords in a table for my sample, but in order to do HSA.query_hsa_tap() I have to do a for loop over them all. It would be nice if table_upload were supported, or any method of vectorizing that query.

Secondly, to download the data, it would be nice if HSA.download_data were vectorized to handle input of multiple observation_ids.

I see this is a more specific version of #682 . But don't worry, one day I'll ask for vectorizing the other archives too.

Start by reading HSA.query_hsa_tap() and HSA.download_data(). Determine how each currently handles a single position or observation ID, then define the vectorized inputs requested in the issue. Done means queries can accept the table of positions and downloads can accept multiple observation_ids without caller-side loops.

Written by the indexing model from the issue text.