DATAREDIS-305 - Add support for HSCAN

`HSCAN` is directly supported by `jedis` and can be emulated for `lettuce` via *eval*.

`SRP` and `JRedis` will throw `UnsupportedOperationException`.

We have modified the `ScanCursor` implementation to take `Collection` instead of `List`. 

Currently naming for scan commands is not consistent for scan, sscan and hscan. There’s a clean up task for those commands when done with all scan related commands.