Add documentation for new RMV public transport sensor (#5947)

* Initial documentation for the rmvtransport sensor.

* Fix name

* Fix typo

* Added missing variable description for max number of journeys.

* Minor wording fix

* Fix setting names after code change.

* Use configuration tag syntax.

* Add logo.

* Update logo file name.

* Fix liquid syntax error.

* Fix config setting name.

* ✏️ Markdown tweaks

source/_components/sensor.rmvtransport.markdown

@@ -0,0 +1,101 @@
+---
+layout: page
+title: "RMV"
+description: "Instructions on how to integrate Rhein-Main public transport departure times into Home Assistant."
+date: 2018-08-02 22:00
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: RMV.png
+ha_category: Transport
+ha_release: 0.76
+ha_iot_class: "Cloud Polling"
+---
+
+The `rvmtransport` sensor will give you the departure time of the next bus, tram, subway, or train at the next station or stop in the Rhein-Main area public transport network. Additional details such as the line number and destination are present in the attributes.
+
+## {% linkable_title Configuration %}
+
+To enable this sensor, add the following lines to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  - platform: rmvtransport
+    next_departure:
+     - station: STATION_OR_STOP_ID
+```
+
+{% configuration %}
+name:
+  description: Name to use in the frontend.
+  required: false
+  default: The default is the station name.
+  type: string
+stationId:
+  description: ID of the stop or station, e.g. 3000010. Visit [the RMV OpenData web site](https://opendata.rmv.de) to find a list of valid IDs.
+  required: true
+  type: string
+destinations:
+  description: "One or multiple final stop names, e.g., 'Frankfurt (Main) Hauptbahnhof' or ['Frankfurt (Main) Hauptbahnhof','Frankfurt (Main) Stadion']. This can be used to only consider a particular direction of travel."
+  required: false
+  type: [string]
+lines:
+  description: "One or more line numbers, e.g., `'S8'` or `['S8', 'RB33', '41']`"
+  required: false
+  default: The default is the station name.
+  type: [string, int]
+products:
+  description: "One or more modes of transport `['U-Bahn', 'Tram', 'Bus', 'S-Bahn', 'RB', 'RE', 'EC', 'IC', 'ICE']`."
+  required: false
+  default: Defaults to all.
+  type: [string]
+time_offset:
+  description: Do not display departures leaving sooner than this number of minutes. Useful if you are a couple of minutes away from the stop.
+  required: false
+  default: The defaults is 0.
+  type: int
+max_journeys:
+  description: Specify the maximal number of journeys.
+  required: false
+  default: The default is 5.
+  type: string
+{% endconfiguration %}
+
+## {% linkable_title Examples %}
+
+### {% linkable_title Full configuration %}
+
+The example below shows a full configuration with three sensors that showcase the various configuration options.
+
+```yaml
+# Example configuration.yaml entry
+sensor:
+  - platform: rmvtransport
+    next_departure:
+      - station: 3000010
+        time_offset: 5
+        destinations:
+          - 'Frankfurt (Main) Flughafen Regionalbahnhof'
+          - 'Frankfurt (Main) Stadion'
+        products:
+          - 'RB'
+          - 'RE'
+          - 'Bus'
+          - 'S'
+      - station: 3006907
+        products: 'Bus'
+        destinations: ['Wiesbaden Dernsches Gelände', 'Mainz Hauptbahnhof']
+        name: Destination
+      - station: 3006904
+        lines: 'S8'
+        max_journeys: 5
+        products: 'S'
+```
+
+The first sensor will return S-Bahn, bus, RB and RE trains departures from Frankfurt Hauptbahnhof to Frankfurt Airport or Stadium that are at least 5 minutes away.
+
+The second sensor returns bus departures from Wiesbaden Hauptbahnhof going to Dernsches Gelände and Mainz Hauptbahnhof. To retrieve the time of the second departure, you would use states.sensor.ENTITY_NAME.attributes.departures[1].time.
+
+The third sensor returns all S-Bahn trains from Mainz Hauptbahnhof for line S8.