DoorBird (#3147)

* Add documentation for DoorBird components

* Update release to 0.52

* Update example configurations

* Update doorbird.markdown

* Update DoorBird release from 0.52 to 0.54

source/_components/camera.doorbird.markdown

@@ -0,0 +1,32 @@
+---
+layout: page
+title: "DoorBird Camera"
+description: "Instructions how to integrate DoorBird video doorbell images into Home Assistant."
+date: 2017-08-06 11:30
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: doorbird.png
+ha_category: Camera
+ha_release: "0.54"
+ha_iot_class: "Local Polling"
+---
+
+The `doorbird` implementation allows you to view the live video and saved images from your [DoorBird](http://www.doorbird.com/) device in Home Assistant.
+
+<p class='note'>
+  You must have the [DoorBird component](/components/doorbird/) configured to use this camera.
+</p>
+
+To enable the camera, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+camera:
+  - platform: doorbird
+```
+
+Configuration variables:
+
+- **last_visitor** (*Optional*): Adds a second camera that shows the last picture taken when someone rang the doorbell. Default is `false`.