I don’t think this exists for CSV and TXT yet, but would be happy to be corrected and would also appreciate such a feature.
At the very least there exists a nice Theme Component for Embedded PDFs so if the txt information also suits such a format, then maybe use LaTeX or something similar to convert it to a pdf?
Alternatively, depending on the content of the files and your python skills, you could convert the contents into markdown, then use the Discourse api to create/update the topic automatically. Or maybe even just find a csv to markdown table converter?