Add documentation for sensor.launch (#7397)

* Add documentation for sensor.launch

* Minor changes

source/_components/sensor.launch.markdown

@@ -0,0 +1,37 @@
+---
+layout: page
+title: "Space Launch sensor"
+description: "Instructions on how to integrate space launch information within Home Assistant."
+date: 2018-11-06 00:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: rocket.png
+ha_category: Sensor
+ha_iot_class: "Cloud Polling"
+ha_release: "0.83"
+---
+
+The `launch` sensor will provide you with information about the next planed space launch.
+
+## {% linkable_title Configuration %}
+
+Add the data to your `configuration.yaml` file as shown in the example:
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  - platform: launch
+```
+
+{% configuration %}
+name:
+  description: Name of the sensor.
+  required: false
+  type: string
+{% endconfiguration %}
+
+The data this platform are presenting are coming from [launchlibrary.net][launchlibrary].
+
+[launchlibrary]: http://launchlibrary.net/