Add feature of setting Urgency (to all users)

Goal – is to give a possibility for users to indicate on how quick they need to get bot's notifications. We have to do it as far as the flow of users / notifications is so intense at times – so telegram API does not let to send all the notifications at once and the queue of notifications lasts for minutes (sometimes to hours).

So, go get a clear indication which users are sensitive to delivery time of notifications – this mechanism is done. On the next stages sending mechanism will take this setting into account in "compose_notifications" and "send_notifications" scripts.

The code is developed, but not well-tested. Function is available in bot if you write "настроить скорость уведомлений". Then there's a list of steps to enter the data.
What we need to do:
- is to check that the existing mechanism is working fine
- that business-logic is sufficient (we give an opportunity to see which notification speed is set and give an opportunity to change it).
- fix if needed
- make this functionality available to everyone when you write to bot "настроить бот".

To track it, i guess the contributor should have an access to prod database and to logs – to be sure that everything can be caught. Admin to grant these accesses be telegram request.

Start by exercising the existing "настроить скорость уведомлений" flow and reviewing the compose_notifications and send_notifications scripts. Check the setting's view and update behavior against the production database and logs, then verify that "настроить бот" exposes the same functionality to every user and that the resulting behavior is adequately tested.

Written by the indexing model from the issue text.