Generic conditions (set parameters directly in model)

[netthier]

I believe it would be useful if conditions could have a free generic parameter that would be set per relation the condition is used in.
This way code duplication can be reduced, which is especially useful in complex conditions.
The following usecase is related to my previous feature request (https://github.com/orgs/openfga/discussions/226) and uses the currently invalid conditions on concentric tuples for demonstrative purposes.

type user
type system
  relations
    define group_can_delete: [user],
    define group_can_invite: [user],
    define group_can_create_doc: [user, user:*]

type group
  relations
    define system: [system]
    define member: [user]
    define can_delete: member and group_can_delete from system with group_kind_in(allowed: ["public"])
    define can_invite: member and group_can_invite from system with group_kind_in(allowed: ["public", "built-in"])
    define can_create_doc: member and group_can_create_doc from system

condition group_kind_in(allowed: list(string), kind: string) {
  kind in allowed
}