change: refactor how boolean env variables are handled, add proper graphql enums

### Additions

* Added `AuthGroup` enum
* Added `Status` enum

### Changes

* field `TeamQuestionnaireStateType.status` type changed to one of `Status` enum values
* field `User.group` and `RestrictedUser.group` type changed to one of `AuthGroup` enum values

### Deletions

* remove redundant `groups` query

Closes #210, #243