title: How to import excel/csv with "File Import" widget in Foundry's Slate?
body: <p><strong>Context:</strong>
  For a data pipeline we need to ingest excel spreadsheets directly into foundry (arriving via email). In order to avoid any manual handling error, we'd like to build a small slate app that basically just uploads an excel sheet and automatically appends it to an existing dataset (given schema, headers, etc.).
  Unfortunately, there is very little documentation on the &quot;File Import&quot; widget or the API that gets called when drag and dropping a file into a folder.</p>
  <p><strong>Idea:</strong> Is there a way of uploading a file with slate? Could this file then be added to a dataset, similarly as with the prompt that opens when dropping it into a folder?</p>