Table download buttons only download visible data

These buttons only download the visible data.
- Try using `server = FALSE` to allow downloading all the data, assuming it's not too slow (https://rstudio.github.io/DT/server.html)
- Modify download file names (https://stackoverflow.com/a/56276939)

Start by locating the table download-button configuration in the Shiny app and review the linked DT server-mode documentation and filename example. The work is done when downloads include all table data without unacceptable slowness and the downloaded files use the intended names.

Written by the indexing model from the issue text.