DATAREDIS-271 - Add support for 'pSetEx'.

Support for 'pSetEx' has been added for 'jedis' and 'srp' while remaining unavailable for 'lettuce' and 'jredis'.

'DefaultValueOperations.set' used with 'TimeUnit.MILLISECONDS' will fall 'setEx' in case 'pSetEx' is not supported by the driver in use.