Add lastfm documentation (#27268)

* Add lastfm documentation

* Apply suggestions from code review

Co-authored-by: G Johansson <goran.johansson@shiftit.se>

* Update lastfm.markdown

---------

Co-authored-by: G Johansson <goran.johansson@shiftit.se>

source/_integrations/lastfm.markdown

@@ -9,38 +9,13 @@ ha_domain: lastfm
 ha_platforms:
   - sensor
 ha_integration_type: integration
+ha_config_flow: true
 ---
 
 The `lastfm` sensor platform will allow you to see whenever a user starts scrobbling, their play count, last song played, and top song played on [Last.fm](https://www.last.fm/).
 
-## Setup
+## Prerequisites
 
 To get an API key you need to create an [API account](https://www.last.fm/api/account/create).
 
-## Configuration
-
-To use Last.fm sensor with your installation, add the following to your `configuration.yaml` file:
-
-```yaml
-# Example configuration.yaml entry
-sensor:
-  - platform: lastfm
-    api_key: YOUR_API_KEY
-    users:
-      - user1
-      - user2
-```
-
-{% configuration %}
-api_key:
-  description: Your Last.fm API key.
-  required: true
-  type: string
-users:
-  description: List of users.
-  required: true
-  type: list
-  keys:
-    username:
-      description: Username of the user to monitor.
-{% endconfiguration %}
+{% include integrations/config_flow.md %}