fill gaps in discharge at Schuylkill and Trenton with PRMS predictions

[galengorski]

I added two functions in the PR:

download_unzip_sb: downloads prms predictions of discharge from science base data release: https://www.sciencebase.gov/catalog/item/5f6a289982ce38aaa2449135 inputs: sb_url: [str] url for downloading zip file prms_predictions: [str] specific file name destination: [str] where the file will be downloaded to outputs: none

fill_discharge_prms:reads in prms predictions of discharge and fills nan gaps for trenton and schuylkill nwis time series inputs: trenton_seg_id_nat: [int] segment id closest to trenton discharge location schuylkill_seg_id_nat: [int] segment id closest to schylkill discharge location nwis_trenton_location: [str] location of munged trenton nwis .csv nwis_schuylkill_location: [str] location of munged schuylkill nwis .csv destination: [str] directory where prms data file is located prms_predictions: [str] name of prms file''' outputs: nwis_trenton_location: [str] same location as input but gap filled discharge nwis_schuylkill_location: [str] same location as input but gap filled discharge