Replace possiblePermissions array in frontend/components/Permissions.js with 'POSSIBLE_PERMISSIONS_QUERY'

[jaridnft]

This would allow someone to ping the API to learn what kind of permissions are available from the backend. Currently, it is an array defined in ./backend/datamodel.graphql:

enum Permission {
  ADMIN
  USER
  ITEMCREATE
  ITEMUPDATE
  ITEMDELETE
  PERMISSIONUPDATE
}