Provide documentation for HP ILO (#789)

* HP ILO component

* Small textual fixes

* Textual updates

Also refer to Integrated Lights-Out instead of only using HP ILO

* Changed ha_release and ha_category

Processed feedback from @balloob:
- changed ha_release to 0.27
- changed ha_category from Sensor to System Monitor

source/_components/sensor.hp_ilo.markdown

@@ -0,0 +1,70 @@
+---
+layout: page
+title: "HP ILO"
+description: "How to integrate HP ILO (Integrated Lights-Out) sensors within Home Assistant."
+date: 2016-08-15 19:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: hewlett_packard_enterprise.png
+ha_category: System Monitor
+ha_release: 0.27
+---
+
+The `hp_ilo` platform allows you to do an API call to the HP ILO (Integrated Lights-Out) sensor of your server, and use this data in (template) sensors.
+
+The component will output the ILO information in the sensor attributes so they can be accessed like that. 
+
+If the ILO only returns a single value (e.g. a temperature or state), it will be put in the state field.
+
+Some more details about what can be retrieved from these sensors is available in the [python-hpilo documentation](http://pythonhosted.org/python-hpilo/)
+
+## Example
+<p class='img'>
+  <img src='{{site_root}}/images/screenshots/hp_ilo.png' />
+</p>
+
+## Usage
+To use this component in your installation, add the following to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  platform: hp_ilo
+  host: IP_ADDRESS or HOSTNAME
+  port: PORT
+  username: USERNAME
+  password: PASSWORD
+  monitored_variables:
+    - server_name
+    - server_fqdn
+    - server_host_data
+    - server_oa_info
+    - server_power_status
+    - server_power_readings
+    - server_power_on_time
+    - server_asset_tag
+    - server_uid_status
+    - server_health
+    - network_settings
+```
+
+Configuration variables:
+
+- **host** (*Required*): The hostname or IP address on which the ILO can be reached
+- **port** (*Optional*): The port on which the ILO can be reached, defaults to port 443
+- **username** (*Required*): The username used to connect to the ILO
+- **password** (*Required*): The password used to connect to the ILO
+- **monitored_variables** array (*Optional*): Information to be collected from the ILO, defaults to `server_name`
+  - **server_name**: Get the name of the server this iLO is managing
+  - **server_fqdn**: Get the fqdn of the server this iLO is managing
+  - **server_host_data**: Get SMBIOS records that describe the host
+  - **server_oa_info**: Get information about the Onboard Administrator of the enclosing chassis
+  - **server_power_status**: Whether the server is powered on or not
+  - **server_power_readings**: Get current, min, max and average power readings
+  - **server_power_on_time**: How many minutes ago has the server been powered on
+  - **server_asset_tag**: Gets the server asset tag
+  - **server_uid_status**: Get the status of the UID light
+  - **server_health**: Get server health information
+  - **network_settings**: Get the iLO network settings