Allow annotation/custom tags on all PlayFab commands

Several commands (GrantItemsToUser, for example) have an Annotation field. This is really useful for Game Support to determine why a specific item was granted.

Most commands, however, do not. It would be good if (at least) the inventory and currency-affecting commands could pass either an annotation or a tag array so we could tag the events in the event manager (there are fields in the events already, they're just unassignable)