Build: publish Kapacitor sdk for UDFs on PyPi

[mtovt]

Description

Hi! This PR adds GitHub Action to release kapacitor_udf package on Python Package Index (solves #930 ).
I have used Poetry as a package manager since it is a modern alternative and provides a simple way to publish packages.

To continue setup, I'm asking InfluxData Team to create an account on PyPi, create an auth token, then add it to secrets. Releases should happen automatically on each release tag. We should update the package version in pyproject.toml.

Context

Currently, we have not convenient to develop Kapacitor UDFs. After this Kapacitor UDF SDK may be easily installed and discovered in a Pythonic way.

It simplifies developing and building.

Affected areas

Affected only Python SDK for Kapacitor UDFs. I have removed setup.py module since Poetry supports all existing functionality.

Note for reviewers:

Check the semantic commit type:

• Feat: a feature with user-visible changes
• Fix: a bug fix that we might tell a user “upgrade to get this fix for your issue”
• Chore: version bumps, internal doc (e.g. README) changes, code comment updates, code formatting fixes… must not be user facing (except dependency version changes)
• Build: build script changes, CI config changes, build tool updates
• Refactor: non-user-visible refactoring
• Check the PR title: we should be able to put this as a one-liner in the release notes