Add support for 'SetLike' keys

[Aklakan]

The StorageComposers API allows for building arbitrarily nested collection topologies in order to realize tuple tables. Currently this limited to 'scalar' keys. This means that only equals or ANY constraints can be realized - i.e. for some tuple table find all rows where the components match ('foo', ANY, 'bar'). With SetLike values we could express constraints such as find all tuples having ids in the range 1 to 5 - e.g. ('foo', ANY, 'bar', [1..5]).

In the end its about enabling support of efficient range queries with the index system.