The webhook url should be calculated at startup, not stored in the state
as otherwise a change in network requires re-configuring the integration
from scratch.
This is particularly important as external network configuration might
change when moving HA between networks, and it's not obvious it needs
to be re-added just for this.
* Use CONF_CLIENT_ID & CONF_CLIENT_SECRET from homeassistant.const
* Fix pylint
* Use in tests
* Search for "client_id"
* Fix tests
* Fix test
* Fix test
* Add and use speed constants
* Add and use meter based volume and area constants
* Add and use more mass unit constants
* Add and use concentration unit constants
* Add and use watts per square meter constant
* Use more time constants
* Use more data constants
* Add and use time related constants
* Sort time constants and reuse them in data rate constants
* Fix greeneyemonitor import
* Fix greeneyemonitor import V2
* Fix failing here_travel_time test
* Add TIME_MONTHS and TIME_YEARS
* Use TIME_MINUTES in opentherm_gw and isy994
* Add and use TIME_MILLISECONDS
* Change inconsistent ones
* Add TIME_MICROSECONDS and TIME_WEEKS
* Use constants in apcupsd and travisci
* Fix import error in upnp sensor.py
* Fix isy994 sensor.py using TIME_YEARS
* Fix dyson tests
* Use TIME_SECONDS in more places
* Use TIME_DAYS in google wifi
* Using latest winthings_api module.
Drastically reduced complexity of tests.
* Removing import source.
* Fixing test requirements.
* Using requests_mock instead of responses module.
* Updating file formatting.
* Removing unused method.
* Adding support for new OAuth2 config flow.
* Addressing PR feedback.
Removing unecessary base_url from config, this is a potential breaking change.
* Addressing PR feedback.
