Status functionality update

[ViktorDronov]

• Backend should setup default status without ability set-it up from the frontend or curl during creation
• In a backend should be functionality to change status to some values from the list (validation needed).
  • In case if someone trying change status to something that not in the allowed list error should be raised

[ViktorDronov]

https://github.com/YuriiBerezan/RestAPI/compare/subtasks-for-the-tree?expand=1

[ViktorDronov]

1st part of this story done
2nd should be done next