* dsl skill

* on_invalid_command in config

* optional arguments

* tests

* Refactoring + Preprocessing in config

* Typo

* Refactoring

* Docstrings

* .rst documentation

* class_name in config

* utterance_batch and user_ids_batch + refactoring

* typo fixed + docstring refactoring

* Optional added

* refactoring

* refactoring context

* redundant bracket

* copyright + refactoring

* return types

* return types

* docstring

* refactoring docstrings

* hotfix

* docs: adapt DSL documentation to the new structure

* docs: docstings refactored

* docs: refactoring

Co-Authored-By: Anton Kiselev <straw.berry.pie@yandex.ru>