Add Data Source info to Input-Geographic tab of Google Sheet

Fill in data source information in the [Input-Geographic](https://docs.google.com/spreadsheets/d/1Fjz8HSnMrlFJVS7CLOfxdjHBhPhIvzMNSNSNSxqsk1M/edit#gid=1528484253) tab of the [HSPF Modules & Variables](https://docs.google.com/spreadsheets/d/1Fjz8HSnMrlFJVS7CLOfxdjHBhPhIvzMNSNSNSxqsk1M/edit#gid=1928838618) Google Sheet.

Similar to #29, but after #28.