Proactive Alexa ChangeReport messages (#18114)

* Alexa: implement auth and proactive ChangeReport messages

* refactor after rebase from dev to use the new AlexaDirective and Response classes

* move to aiohttp; cleanup

* better function name

* move endpoint to config

* allow passing token function

* remove uneeded state get

* use iterable directly

Co-Authored-By: abmantis <abmantis@users.noreply.github.com>

* missing delete from previous commit

* checks for when user has no auth config

* update cloud component

* PR suggestions

* string lint

* Revert "string lint"

This reverts commit a05a1f134c9ebc7a6e67c093009744f142256365.

* linters are now happier

* more happy linters

* use internal date parser; improve json response handling

* remove unused import

* use await instead of async_add_job

* protect access token update method

* add test_report_state

* line too long

* add docstring

* Update test_smart_home.py

* test accept grant api

* init prefs if None

* add tests for auth and token requests

* replace global with hass.data

* doc lint

homeassistant/components/alexa/const.py

@@ -10,6 +10,9 @@ CONF_DISPLAY_URL = 'display_url'
 
 CONF_FILTER = 'filter'
 CONF_ENTITY_CONFIG = 'entity_config'
+CONF_ENDPOINT = 'endpoint'
+CONF_CLIENT_ID = 'client_id'
+CONF_CLIENT_SECRET = 'client_secret'
 
 ATTR_UID = 'uid'
 ATTR_UPDATE_DATE = 'updateDate'
@@ -21,3 +24,5 @@ ATTR_REDIRECTION_URL = 'redirectionURL'
 SYN_RESOLUTION_MATCH = 'ER_SUCCESS_MATCH'
 
 DATE_FORMAT = '%Y-%m-%dT%H:%M:%S.0Z'
+
+DEFAULT_TIMEOUT = 30