Create automation_telegram_presence_alert (#1729)

source/_cookbook/ automation_telegram_presence_alert

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+This will send an alert when someone in your known devices list connects to the networt via wifi. In other words, when someone arrives home.
+It will only work if you are using nmap or similar component. 
+I am using the ddwrt component to get a list of connected devices on my network.
+
+follow these isntructions to get api_key and chat_id
+https://home-assistant.io/components/notify.telegram/
+
+// Add the telegram component
+notify:
+  - name: Telegram
+    platform: telegram
+    api_key: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+    chat_id: xxxxxxxxx
+    
+//add the automation component
+//Note: device_name_here should be whatever the device is named in known devices file. 
+
+automation:
+  trigger:
+    platform: state
+    entity_id: device_tracker.device_name_here
+    from: 'not_home'
+    to: 'home'
+  action:
+    service: notify.Telegram
+    data:
+      message:  "Person is now home"