[FR] Add an epic selection to the userstory creation interface

[kosdmit]

Please describe the problem / need you are trying to solve. It's impossible to choose an epic for a user story in the create user story interface. Now I create a new user story in two steps: creating it and then opening the editing interface to set the epic.

Describe the feature or the improvement you'd like and what are you trying to achieve. It would be better if we added the epic selection for example here: