Add documentation for pjlink media player component (#5585)

* add documentation for pjlink media player component

* Remove optional parameters from configuration sample.
Update version to 0.73
Add logo

* ⬆️ ha_release 0.76

source/_components/media_player.pjlink.markdown

@@ -0,0 +1,53 @@
+---
+layout: page
+title: "PJLink"
+description: "Instructions on how to integrate PJLink enabled projectors into Home Assistant."
+date: 2018-06-21 08:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: pjlink.png
+ha_category: Media Player
+ha_release: 0.76
+ha_iot_class: "Local Polling"
+---
+
+The `pjlink` platform allows you to control from Home Assistant, projectors with support for the [PJLink protocol](http://pjlink.jbmia.or.jp/english/index.html).
+
+## {% linkable_title Configuration %}
+
+To add a PJLink projector  to your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+media_player:
+  - platform: pjlink
+    host: 192.168.1.2
+```
+
+{% configuration %}
+host:
+  description: IP address or hostname of the device. Example:`192.168.1.2`.
+  required: true
+  type: string
+port:
+  description: port on which the PJLink service runs on the device.
+  required: false
+  type: int
+  default: 4352
+name:
+  description: Name of the device.
+  required: false
+  type: string
+  default: name of the device as returned by PJLink.
+encoding:
+  description: Character encoding to use to communicate with the device.
+  required: false
+  type: string
+  default: utf-8
+password:
+  description: Password to authenticate with the projector.
+  required: false
+  type: string
+{% endconfiguration %}