Java: Add INFO() commands to java client

[acarbonetto]

Issue #, if available:

This PR is dependent to: #917

Description of changes:
This PR adds get/set/ping/info calls to the standalone, and cluster-mode:

• standalone
  • info
  • info with sections
• cluster
  • info
  • info with routing
  • info with sections
  • info with sections & routing

note: info() command returns different sections in Redis version 6 vs version 7. IT tests have added the Redis version system variable to help test results expect version-specific results.

Examples:

// Single commands
RedisClient client = RedisClient.createClient(config).get();
String infoResult = client.info().get();
String infoResultWithOptions = client.info(InfoOptions.builder().section(EVERYTHING).build()).get();

// Cluster-mode single commands
RedisClusterClient clusterClient = RedisClusterClient.createClient(config).get();
String infoResult = clusterClient.info(ALL_NODES).get();
String infoResultWithOptions = client.info(InfoOptions.builder().section(EVERYTHING).build(), ALL_NODES).get();

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[barshaul]

Without routing the info request is routed to multi-nodes (all primaries), so the return value is a map of strings. should be documented

[barshaul]

Can you add an example, so it would be clearer that getMulti needs to be called in these functions by default

[acarbonetto]

How is this:

    /**
     * Get information and statistics about the Redis server. DEFAULT option is assumed. The command
     * will be routed to all primaries.
     *
     * @see <a href="https://redis.io/commands/info/">redis.io</a> for details. {@link
     *     InfoOptions.Section#DEFAULT} option is assumed.
     * @return Response from Redis cluster with a <code>Map{@literal <String, String>}</code> with each address
     *     as the key and its corresponding value is the information for the node.
     * @example
     *     <p><code>
     *     {@literal Map<String, String>} routedInfoResult = clusterClient.info().get().getMultiValue();
     *     </code>
     */

[barshaul]

Should be mentioned that it's being sent to all primaries and that the return type is a map

[barshaul]

[0])[2])[2] is the node ID == "92d73b6eb847604b63c7f7cbbf39b148acdd1318", why do you need it? why do you need to run cluster slots at all?

If you want to have a routing of a primary you can simply do new SlotKeyRoute("foo", PRIMARY);, we're covering all slots when we create the cluster so it would simply send the request to the primary that holds the slot of crc16("foo")

[acarbonetto]

This is just testing that we can do this. It's maybe not the most efficient command.

[barshaul]

LGTM, please fix the comments

[Yury-Fridlyand]

Is null accepted here?

Suggested change

	Info, new String[0], response -> ClusterValue.of(handleObjectOrNullResponse(response)));
	Info, new String[0], response -> ClusterValue.of(handleObjectResponse(response)));

[acarbonetto]

I suppose that makes sense.