Refine the return value of forceCloseHandles API

[sima-zhu]

We return Iterable currently which might not make sense to customer. Think about to return how many handles actually closed.

Need two APIs:

1. with handleId as arg
2. without args for forceCloseAll

[sima-zhu]

@alzimmermsft

[kurtzeborn]

@alzimmermsft, you were saying the only useful data the REST api returns is integers. Take a look and if that's correct, there's not much we can do here, so it should be closed.

[alzimmermsft]

The return type of the methods have been changed to PagedFlux<Integer> and PagedIterable<Integer> which is correct based on the API documentation. The API will need to be updated to include better overloads.

[vhvb1989]

No need to add a new API overload for closeAll() since this method can take an asterisk ('*') as a wildcard string to specify all handles and that is documented in JavaDoc