Queries with unicode in query name fails downloading result file

[arikfr]

This just happened on deploy preview. Sentry error:
https://sentry.io/share/issue/b8268b7c97784a30b67c512332a8d779/

Some possible solutions:

1. Implement a solution similar to Fix send_file's attachment_filename to work with non-ascii filenames pallets/flask#2223.
2. Switch to using Flask's send_file method instead of handling this on our own (need to make sure that we always have a file-like object at hand and that the behavior consistent with our current one).
3. Try quoting the filename, as suggested here: UnicodeEncodeError: 'ascii' codec can't encode characters in position 151-165: ordinal not in range(128) benoitc/gunicorn#1214 (comment).

3 is the simplest, 2 is probably the most future proof.

[jezdez]

+1 on (2)