Add documentation for googlehome device_tracker. (#7357)

* Add documentation for googlehome device_tracker.

* Corrected typo

* update descriptions

* ✏️ Spelling

source/_components/device_tracker.googlehome.markdown

@@ -0,0 +1,41 @@
+---
+layout: page
+title: "Google Home Bluetooth tracker"
+description: "Instructions on how to use Google Home to track devices in Home Assistant."
+date: 2018-11-04 00:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: google_home.png
+ha_release: 0.83
+ha_category: Presence Detection
+ha_iot_class: "Local Polling"
+---
+
+The `googlehome` platform allows you to detect presence using an [unofficial Google Home API][googlehomeapi].
+
+## {% linkable_title Configuration %}
+
+To integrate Google Home Bluetooth tracker in Home Assistant, add the following section to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+device_tracker:
+  - platform: googlehome
+    host: IP_ADDRESS
+```
+
+{% configuration %}
+host:
+  description: The IP address of the Google Home unit.
+  required: true
+  type: string
+rssi_threshold:
+  description: The threshold for the RSSI signal of the device.
+  required: false
+  default: -70
+  type: integer
+{% endconfiguration %}
+
+[googlehomeapi]: https://rithvikvibhu.github.io/GHLocalApi/