feat: adds order opt to sortedset getRank

[eaddingtonwhite]

Currently for sortedSetGetRank we only support fetching in Ascending order.

await momento.sortedSetGetRank('my-cache', 'my-sorted-set', 'my-element');

This PR adds optional call options to sortedSetGetRank to sort the sorted set by Descending or Ascending order when determining the rank of the passed element. So can call like this now:

await momento.sortedSetGetRank('my-cache', 'my-sorted-set', 'my-element', {
    order: SortedSetOrder.Descending
});