CollectionConfigOf: StorageDescriptor<[Key: number], {
    max_supply?: number;
    mint_settings: {
        default_item_settings: bigint;
        end_block?: number;
        mint_type: Enum<{
            HolderOf: number;
            Issuer: undefined;
            Public: undefined;
        }>;
        price?: bigint;
        start_block?: number;
    };
    settings: bigint;
}, true, never>

Config of a collection.