Add command to return my balance, balance for all users

[Ovaday]

To change:

• [x] /tg_routine/commandHelpers.py/user_balance_helper
• [x] /tg_routine/commandHelpers.py/all_users_balance_helper

If there is a user_id needed for test, use Chat.objects.all() and select one user_id from the available here. You can even insert your user by creating new Chat with your chat_id (you can ask me if you don't know your TG chat ID) and then calling the chat.save(). For test or some code invocation, use:

• [x] /website/views.py/test_endpoint After launching the web server it is available for retrieval at http://127.0.0.1:8000/test/

Cooperate with other people from the command to finish the task and create the PR which should be well-formed.

[Ovaday]

@NastyaKolbina If that is ready, please create the PR