feat: Line Channel (#2904)

- Ability to configure line bots as a channel in chatwoot
- Receive a message sent to the line bot in chatwoot
- Ability to reply to line users from chatwoot

fixes: #2738

app/services/line/send_on_line_service.rb

@@ -0,0 +1,11 @@
+class Line::SendOnLineService < Base::SendOnChannelService
+  private
+
+  def channel_class
+    Channel::Line
+  end
+
+  def perform_reply
+    channel.client.push_message(message.conversation.contact_inbox.source_id, [{ type: 'text', text: message.content }])
+  end
+end