Refactor Enocean part 1 (#35927)

* First step of an EnOcean integration refactoring, including code reorganisation and support of a setup config flow

* Moved title to root of strings file

* Fixed pre-commit checks failures

* Fixed linter errors

* Updated formatted string format in logs

* Removed leftover comment

* Multiple changes after PR change requests.
Using an import flow for yaml config, removed unnecessary logs, added proper unload in __init__ and EnOceanDongle
Replaced config state machine by several flows.
Serial port validity check done in the EnOceanDongle class asynchronously, removed unique ID from config flow
Multiple cosmetic changes

* Multiple changes after PR change requests

* Added variable to store default value, as setdefault was caught returning None when the empty dict literal was passed as an argument

* Literal used directly

* Added tests for EnOcean config flows, changed static methods to bundle methods for bundle

* Updated variable name

* Added missing mock to test, replaced repeated magic strings by constants

* Changed imports to avoid an unused import warning from pylint on DOMAIN

* Adding pylint exception for unused import

* Added proper propagation of setup and unload to platforms, removed dead code, some syntax changes

* Removed setup_entry forwarding as the entities can only be configured using yaml

* Removed forwarding of unload

* Enabled code coverage for config flow only

* Clean up coveragerc

Co-authored-by: Martin Hjelmare <marhje52@gmail.com>