Switch rfxtrx to config entries (#37794)

* Switch to config flow setup

* Add minimal test for config flow

* Add myself as codeowner and address some review concerns

* Address some further review comments

homeassistant/components/rfxtrx/config_flow.py

@@ -0,0 +1,22 @@
+"""Config flow for RFXCOM RFXtrx integration."""
+import logging
+
+from homeassistant import config_entries
+
+from . import DOMAIN
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class ConfigFlow(config_entries.ConfigFlow, domain=DOMAIN):
+    """Handle a config flow for RFXCOM RFXtrx."""
+
+    VERSION = 1
+    CONNECTION_CLASS = config_entries.CONN_CLASS_LOCAL_PUSH
+
+    async def async_step_import(self, import_config=None):
+        """Handle the initial step."""
+
+        await self.async_set_unique_id(DOMAIN)
+        self._abort_if_unique_id_configured(import_config)
+        return self.async_create_entry(title="RFXTRX", data=import_config)