refactor: create a ContextMixin class, and extract methods into there (#494)

* refactor: create a ContextMixin class, and extract methods into there

* docs: update context typehints and pyi file

* ci: correct from checks.

* fix: adjust payload creation

* ci: correct from checks.

* ci: correct from checks.

* refactor: change ContextMixin to _Context

* fix: forgotten name change

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: Catalyst4222