Combine low level tuple implementations

Currently, there are two low level [tuple](https://github.com/apple/foundationdb/blob/master/design/tuple.md) implementations that are very similar:

* [bindings/flow/Tuple.h](https://github.com/apple/foundationdb/blob/master/bindings/flow/Tuple.h)
* [fdbclient/include/fdbclient/Tuple.h](https://github.com/apple/foundationdb/blob/main/fdbclient/include/fdbclient/Tuple.h)

The implementation in `fdbclient` supports fewer types than the implementation in `bindings`. Perhaps they can be collapsed to avoid code duplication and provide users access to all tuple types.