Entur upgrade to v0.2.0: async polling, number of departures, omit non boarding departures (#22001)

* The Great Migration

* removed outdated tests

* Upgraded enturclient to v0.2.0
- client has gone async
- configurable if non boarding departures should be omitted from result
- configurable how many departures should be shown
- more clear which attributes are included and when

* reduced nesting and clearing of attributes

* Removed test data

* ensure attribution and stop id in attributes

* docstring fixes

* fix rebase errors
went a bit too fast on continue on one of the conflicts..

* fix test requirements comment from gen

script/gen_requirements_all.py

@@ -54,7 +54,6 @@ TEST_REQUIREMENTS = (
     'dsmr_parser',
     'eebrightbox',
     'emulated_roku',
-    'enturclient',
     'ephem',
     'evohomeclient',
     'feedparser-homeassistant',