Add config flow for cloudflare (#41167)

* add config flow for cloudflare

* Create const.py

* work on flow.

* remove const.

* lint.

* Apply suggestions from code review

Co-authored-by: J. Nick Koston <nick@koston.org>

* Update config_flows.py

* Update homeassistant/components/cloudflare/strings.json

* Apply suggestions from code review

* Apply suggestions from code review

* Apply suggestions from code review

* Update strings.json

* Apply suggestions from code review

* Update __init__.py

* Update __init__.py

Co-authored-by: J. Nick Koston <nick@koston.org>

tests/components/cloudflare/conftest.py

@@ -0,0 +1,28 @@
+"""Define fixtures available for all tests."""
+from pytest import fixture
+
+from . import _get_mock_cfupdate
+
+from tests.async_mock import patch
+
+
+@fixture
+def cfupdate(hass):
+    """Mock the CloudflareUpdater for easier testing."""
+    mock_cfupdate = _get_mock_cfupdate()
+    with patch(
+        "homeassistant.components.cloudflare.CloudflareUpdater",
+        return_value=mock_cfupdate,
+    ) as mock_api:
+        yield mock_api
+
+
+@fixture
+def cfupdate_flow(hass):
+    """Mock the CloudflareUpdater for easier config flow testing."""
+    mock_cfupdate = _get_mock_cfupdate()
+    with patch(
+        "homeassistant.components.cloudflare.config_flow.CloudflareUpdater",
+        return_value=mock_cfupdate,
+    ) as mock_api:
+        yield mock_api