Fix section "2-Create Sentiment Service in e2e tut (#6422)

The latest func cli generates a different Python function template than
shown in the tutorial. There is no `setup.py` anymore and the project
uses a toml file for configuration. The entire section was updated and
code was corrected.

Issue #6417.

Signed-off-by: Stanislav Jakuschevskij <[email protected]>
Co-authored-by: Stanislav Jakuschevskij <[email protected]>

Author: knative-prow-robot