### Description

It should be enough to have ShardId + nodeId key in `routingToDataPath` to find the necessary data path. 
Changing the key would allow us to minimize the size of ClusterInfo size and find the data path when shard changes its status.

`ClusterInfo` might be sent over the wire when cluster allocation explain is executed with `includeDiskInfo=true`.
ShardRouting -> ShardId + nodeId conversion is trivial. The oposit would require additional information that could be faked.

Current key is also used in here:
https://github.com/elastic/elasticsearch/blob/9ebbe1c62bf0157d332f20f392544a1921a710df/server/src/main/java/org/elasticsearch/cluster/ClusterInfo.java#L149-L154
where it produces a string with ShardRouting#shortSummary that is excessive and might be simplified to ShardId + nodeId as well
server/src/test/java/org/elasticsearch/cluster/DiskUsageTests.java
assertThat(du.getUsedDiskAsPercentage(), equalTo(100.0 - (100.0 * free / total)));
            }
        }
    }
    public void testFillShardLevelInfo() {
        final Index index = new Index("test", "0xdeadbeef");
        ShardRouting test_0 = ShardRouting.newUnassigned(
            new ShardId(index, 0),
            false,
            PeerRecoverySource.INSTANCE,
            new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, "foo")
        );
        test_0 = ShardRoutingHelper.initialize(test_0, "node1");
        test_0 = ShardRoutingHelper.moveToStarted(test_0);
        Path test0Path = createTempDir().resolve("indices").resolve(index.getUUID()).resolve("0");
        CommonStats commonStats0 = new CommonStats();
        commonStats0.store = new StoreStats(100, 101, 0L);
        ShardRouting test_1 = ShardRouting.newUnassigned(
            new ShardId(index, 1),
            false,
            PeerRecoverySource.INSTANCE,
            new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, "foo")
        );
        test_1 = ShardRoutingHelper.initialize(test_1, "node2");
        test_1 = ShardRoutingHelper.moveToStarted(test_1);
        Path test1Path = createTempDir().resolve("indices").resolve(index.getUUID()).resolve("1");
        CommonStats commonStats1 = new CommonStats();
        commonStats1.store = new StoreStats(1000, 1001, 0L);
        CommonStats commonStats2 = new CommonStats();
        commonStats2.store = new StoreStats(1000, 999, 0L);