Create testing functionality via temporary bots

[essare-rimaz]

• before we implement changes, those should be tested
• some of these changes can only be evaluated visually within Telegram UI
• to give every tester the possibility to test these independently, they need a way how to create their own temporary chatbot
• since that is quite complicated, the creation/deletion of these temporary bots was automated via telethon library
• it still requires them to make changes with the credentials.yml file, however, it is still much easier than doing the entire process
• some changes were made specifically to counter the possibility of sharing sensitive information