ks-email-parser python update

[b1r3k]

lxml fails on 3.11 if lxml < 4
lxml >= 3 works

1. find . -iname '.py' -not -path "/venv/*" -exec pyupgrade --py311-plus {} +
2. transition to nose2
3. enum changed behaviour of str()
4. remove dependency on async_test
5. transition to pytest - https://github.com/pytest-dev/nose2pytest
6. update travis CI

• what about different CI system?
  • github actions?
  • circle CI? (we already use it on mobile side)

7. ansible playbook update
8. Optional: transition to pyproject.toml
9. Optional: aiohttp update?

requires: https://github.com/KeepSafe/email-service/issues/419

Findings

• lxml 3.x does not compile on python 3.11 (at least when using python distribution provided by pyenv). lxml >= 4 compiles fine but tests may require some adjustment (output diff could have been caused by beautifulsoup in fact)