Update device_tracker.owntracks_http.markdown (#5172)

* Update device_tracker.owntracks_http.markdown

Show battery value reported by owntracks

* Update device_tracker.owntracks_http.markdown

Fix

* Fix configuration sample

source/_components/device_tracker.owntracks_http.markdown

@@ -34,3 +34,30 @@ Open OwnTracks and go to Connection preferences:
  - Identification: Turn **Authentication** on, username `homeassistant` and password is your API password that you use to login to Home Assistant.
  
 Host example: If I host my Home Assistant at `https://example.duckdns.org`, my name is Paulus and my phone is a Pixel I would set the host to be `https://example.duckdns.org/api/owntracks/paulus/pixel`. This will result in an entity with an ID of `device_tracker.paulus_pixel`. You can pick any name for the user and the device.
+
+Since the battery data is available as an attribute of the device tracker entity, it can be tracked with a [`template` sensor](/components/sensor.template/).
+
+{% raw %}
+```yaml
+# Example configuration.yaml entry
+sensor:
+  - platform: template
+    sensors:
+      pixel_battery:
+        friendly_name: Pixel of Paulus
+        unit_of_measurement: "%"
+        value_template: '{{ states.device_tracker.paulus_pixel.attributes.battery|int }}'
+        icon_template: >-
+          {% set battery_level = states.device_tracker.paulus_pixel.attributes.battery|default(0)|int %}
+          {% set battery_round = (battery_level / 10) |int * 10 %}
+          {% if battery_round >= 100 %}
+            mdi:battery
+          {% elif battery_round > 0 %}
+            mdi:battery-{{ battery_round }}
+          {% else %}
+            mdi:battery-alert
+          {% endif %}
+        entity_id: 
+        - device_tracker.paulus_pixel
+```
+{% endraw %}