New: allowed mongoQueries.resources filter for the cluster endpoints

[rmgraham]

On the cluster endpoints, you can now add:

"mongoQueries": {
    "resources": {
        "_id": "5eed111fc481a71a8f5fbfa3" //or something else
    }
}

and itll apply that filter to any nested resources you want to load.
In a future PR, this will work on all endpoints, and youll be able to do the same filters against channels/subs/groups/etc