Acceptance Criteria

• Should add form for granting access to users
• Should check for validity of entered usernames
• Should list available permissions for selected role
• Should allow changing role for a user through update form

SpaceBindingRequest CR: https://docs.google.com/document/d/1hWaFvCfsEXrbqs8ndDR0JPjKROXYJkvj1ZCnio4P1WU/edit#heading=h.3qfeu3eg5ecu
Permissions & roles: https://redhat-appstudio.github.io/docs.appstudio.io/Documentation/main/getting-started/roles_persmissions