Axis config flow (#18543)

* Initial draft

* Add tests for init
Fix hound comments

* Add tests for device
Change parameter handling to make device easier to test

* Remove superfluous functionality per Martins request

* Fix hound comments

* Embedded platforms

* Fix device import

* Config flow retry

* Options default values will be set automatically to options in config entry before component can be used

* Clean up init
Add populate options
Fix small issues in config flow
Add tests covering init

* Improve device tests

* Add config flow tests

* Fix hound comments

* Rebase miss

* Initial tests for binary sensors

* Clean up
More binary sensor tests

* Hound comments

* Add camera tests

* Fix initial state of sensors

* Bump dependency to v17

* Fix pylint and flake8

* Fix comments

homeassistant/components/axis/errors.py

@@ -0,0 +1,22 @@
+"""Errors for the Axis component."""
+from homeassistant.exceptions import HomeAssistantError
+
+
+class AxisException(HomeAssistantError):
+    """Base class for Axis exceptions."""
+
+
+class AlreadyConfigured(AxisException):
+    """Device is already configured."""
+
+
+class AuthenticationRequired(AxisException):
+    """Unknown error occurred."""
+
+
+class CannotConnect(AxisException):
+    """Unable to connect to the device."""
+
+
+class UserLevel(AxisException):
+    """User level too low."""