add tool to query OSCAR to support station management (#469)

[tomkralidis]

Implements #469

[maaikelimper]

The get-function described itself as "Publishes collection of stations to API config and backend". The current implementation only prints a line.
Should the get-function update the station_list.csv (our current backend) ?
Or we write in the documentation that the user has to take care of getting the line in the csv :
wis2box metadata station get -wsi 0-20000-01515 >> /data/wis2box/metadata/station_list.csv

[tomkralidis]

I've fixed the docstring accordingly. We should keep the shell redirection option which gives the user the ability to review before potentially adding to the station list.