also str representation of unicode character is different.

py2/py3: import InstanceDict from DocumentTemplate._DocumentTemplate instead of deprecated DocumentTemplate.DT_Util.

use urlsplit instead, prepending '//' like discussed in https://bugs.python.org/issue27485#msg270215

fixes errors on python3, File needs bytes

This not closed comment tag was probably a problem for Chameleon, this
is from a commit from Aurélien in 2021, adjusted by Jérome in 2023 (to
actually remove the code that were commented out, not just removing the
comment and leaving the code)

New cloudooo uses text/csv as mimetype for CSV, which is correct, but this revealed issues in ERP5:
 - ERP5 did not detect text/csv for csv extensions
 - downloading a file with content type text/csv caused an error

See merge request !1859

See merge request !1860

  in addition to None, id can be an empty list on this case

See merge request !1858