telegram_bot platform to only send messages (#8186) (#2882)

* add telegram_bot/onlysend doc for #8186

* change of platform name and small rewrite

* fix new platform name

source/_components/telegram_bot.broadcast.markdown

@@ -0,0 +1,37 @@
+---
+layout: page
+title: "Telegram broadcast"
+description: "Telegram support to send messages only"
+date: 2017-06-24 11:20
+sidebar: true
+comments: false
+sharing: true
+footer: true
+logo: telegram.png
+ha_category: Telegram chatbot
+ha_release: 0.48
+---
+
+Telegram implementation to support **sending messages only**. Your Home Assistant instance does not have to be exposed to the Internet and there is no polling to receive messages sent to the bot.
+
+To integrate this into Home Assistant, add the following section to your `configuration.yaml` file:
+
+```yaml
+# Example configuration.yaml entry
+
+telegram_bot:
+  - platform: broadcast
+    api_key: <telegram api key>
+    allowed_chat_ids:
+      - 12345
+      - 67890
+```
+
+Configuration variables:
+
+- **allowed_chat_ids** (*Required*): A list of user in the `user_id` Telegram format enabled to interact to webhook
+- **api_key** (*Required*): The API token of your bot.
+- **parse_mode** (*Optional*): Default parser for messages if not explicit in message data: 'html' or 'markdown'. Default is 'markdown'.
+
+To get your `chat_id` and `api_key` follow the instructions [here](/components/notify.telegram/).
+

source/_components/telegram_bot.markdown

@@ -17,6 +17,7 @@ Use Telegram on your mobile or desktop device to send and receive messages or co
 
 This component creates notification services to send, or edit previously sent, messages from a [Telegram Bot account](https://core.telegram.org/bots) configured either with the [polling](/components/telegram_bot.polling/) method or with the [webhooks](/components/telegram_bot.webhooks/) one, and trigger events when receiving messages.
 
+If you don't need to receive messages, you can use the [broadcast](/components/telegram_bot.broadcast/) platform instead.
 
 ### {% linkable_title Notification services %}
 Available services: `send_message`, `send_photo`, `send_document`, `send_location`, `edit_message`, `edit_replymarkup`, `edit_caption`, `answer_callback_query`.