feat: Telegram Channel (#2901)

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

fixes: #1843

spec/factories/channel/channel_telegram.rb

@@ -0,0 +1,16 @@
+FactoryBot.define do
+  factory :channel_telegram, class: 'Channel::Telegram' do
+    bot_token { '2324234324' }
+    account
+
+    before(:create) do |channel_telegram|
+      # we are skipping some of the validation methods
+      channel_telegram.define_singleton_method(:ensure_valid_bot_token) { return }
+      channel_telegram.define_singleton_method(:setup_telegram_webhook) { return }
+    end
+
+    after(:create) do |channel_telegram|
+      create(:inbox, channel: channel_telegram, account: channel_telegram.account)
+    end
+  end
+end