Add WWLLN docs (#9802)

* Add WWLLN docs

* Updated docs

* Added more docs and a screenshot

* Added window parameter

* ✏️ Tweak

source/_components/wwlln.markdown

@@ -0,0 +1,82 @@
+---
+layout: page
+title: "World Wide Lightning Location Network (WWLLN)"
+description: "Instructions on how to integrate WWLLN within Home Assistant."
+date: 2019-07-06 23:17
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: wwlln.jpg
+ha_category: Geolocation
+ha_release: 0.96
+ha_iot_class: Cloud Polling
+ha_config_flow: true
+---
+
+The `wwlln` integration displays lightning strike information from the
+[World Wide Lightning Location Network (WWLLN)](http://wwlln.net).
+
+Entities are generated, updated and removed automatically with each update 
+from the feed. Each entity defines latitude and longitude and will be shown 
+on the default map automatically, or on a map card by defining the source 
+`wwlln`. The distance (in kilometers or miles, depending on your unit system)
+is available as the state of each entity.
+
+<p class='img'>
+  <img src='{{site_root}}/images/screenshots/wwlln-feed-map.png' />
+</p>
+
+New data is returned every 5 minutes.
+
+## Configuration
+
+To retrieve data from the WWLLN, add the following to your `configuration.yaml`
+file:
+
+```yaml
+wwlln:
+```
+
+{% configuration %}
+latitude:
+  description: The latitude you want to monitor; defaults to the value defined in `configuration.yaml`.
+  required: false
+  type: float
+longitude:
+  description: The longitude you want to monitor; defaults to the value defined in `configuration.yaml`.
+  required: false
+  type: float
+radius:
+  description: The radius around your location to monitor; defaults to 25 km or mi (depending on the unit system defined in your `configuration.yaml`).
+  required: false
+  type: int
+window:
+  description: The amount of time before now for which strikes should be considered "active" and shown in the UI.
+  required: false
+  type: time
+{% endconfiguration %}
+
+## State Attributes
+
+The following state attributes are available for each entity in addition to 
+the standard ones:
+
+| Attribute          | Description |
+|--------------------|-------------|
+| latitude           | Latitude of the lightning strike. |
+| longitude          | Longitude of the lightning strike. |
+| source             | `wwlln` to be used in conjunction with the `geo_location` automation trigger. |
+| external_id        | The external ID used in the feed to identify the earthquake in the feed. |
+| publication_date   | Date and time when this event occurred. |
+
+
+## Full Configuration
+
+```yaml
+# Example configuration.yaml entry
+wwlln:
+    radius: 100
+    latitude: 37.39
+    longitude: -5.99
+```