Add ESPHome native API discovery

[OttoWinter]

Description:

Waiting for home-assistant-libs/netdisco#229 and new netdisco release

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.

[OttoWinter]

So the 0.85.0 release cutoff is waiting... What's the status on a netdisco release 😜 I was hoping to advertise this new release together with automatic discovery, but it's not a deal-breaker if it's not there just yet either.

(If needed, I can also do the release now that I know more about pypi)

[balloob]

Released 2.3.0. Bump it in this PR and I'll cherry pick it into the beta.

[balloob]

This PR did not cleanly apply to the rc branch.

Here is the beginning of the diff

diff --cc tests/components/esphome/test_config_flow.py
index d90db501a,1291aa531..000000000
--- a/tests/components/esphome/test_config_flow.py
+++ b/tests/components/esphome/test_config_flow.py
@@@ -193,28 -188,62 +193,90 @@@ async def test_user_invalid_password(ha
      }


++<<<<<<< HEAD
 +async def test_user_login_connection_error(hass, mock_api_connection_error,
 +                                           mock_client):
 +    """Test user step with connection error during login phase."""
 +    flow = config_flow.EsphomeFlowHandler()
 +    flow.hass = hass
 +    await flow.async_step_user(user_input=None)
 +
 +    mock_client.device_info.return_value = mock_coro(
 +        MockDeviceInfo(True, "test"))
 +
 +    await flow.async_step_user(user_input={
 +        'host': '127.0.0.1',
 +        'port': 6053,
 +    })
 +
 +    mock_client.connect.side_effect = mock_api_connection_error
 +    result = await flow.async_step_authenticate(user_input={
 +        'password': 'invalid'
 +    })
 +
 +    assert result['type'] == 'form'
 +    assert result['step_id'] == 'authenticate'
 +    assert result['errors'] == {
 +        'base': 'connection_error'
 +    }
++=======
+ async def test_discovery_initiation(hass, mock_client):
+     """Test discovery importing works."""
+     flow = config_flow.EsphomeFlowHandler()
+     flow.hass = hass
+     service_info = {
+         'host': '192.168.43.183',
+         'port': 6053,
+         'hostname': 'test8266.local.',
+         'properties': {}
+     }

I resolved it by keeping both pieces of code.