[Parimutuel] Permissioned mode

[sea212]

Maybe some group would like to internally bet within the group. For this, an option should be available to make the Parimutuel market permissioned. The easiest approach would be to add a list of initial accounts and a manager account who can manage that list. A more advanced solution would incorporate organizational identity trees from native identities and external identity providers like KILT. Initially, the account list and manager approach should be sufficient.