Redirect server output

[ludwigme]

Added options to redirect output from the started Redis instances.
Usage:

RedisServerBuilder serverBuilder = RedisServer.builder()//
		.outTo(System.out)//
		.errTo(System.err)//
		.redisExecProvider(REDIS_EXEC_PROVIDER);

RedisSentinelBuilder sentinelBuilder = new RedisSentinelBuilder()//
		.outTo(System.out)//
		.errTo(System.err)//
		.redisExecProvider(REDIS_EXEC_PROVIDER);

// creates a cluster with 3 sentinels, quorum size of 2 and 3 replication
// groups, each with one master and one slave
cluster = RedisCluster.builder()//
		.withServerBuilder(serverBuilder)//
		.withSentinelBuilder(sentinelBuilder)//
		.ephemeral().sentinelCount(3).quorumSize(2).replicationGroup("master1", 1)
		.replicationGroup("master2", 1).replicationGroup("master3", 1).build();
cluster.start();

[robertotru]

I don't have time to test this now. If someone else could peer review the PR I'd be glad to proceed.

[OzWolf]

Reviewed. Both the PrintReaderRunnable jobs for error and output streams are executing on the same single threaded executor. If it was me, I'd be happier with some additions to the tests proving that enabling both the error and output streams at the same time don't cause an executor lock and that future changes don't accidentally cause one either.

[zHaytam]

Any news on this?