### 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/main/java/org/elasticsearch/cluster/routing/ShardRouting.java
: "ShardRouting is a relocation target but current node id isn't equal to source relocating node."
                + " This ["
                + this
                + "], other ["
                + other
                + "]";
        assert b == false || this.shardId.equals(other.shardId)
            : "ShardRouting is a relocation target but both indexRoutings are not of the same shard id."
                + " This ["
                + this
                + "], other ["
                + other
                + "]";
        assert b == false || this.primary == other.primary
            : "ShardRouting is a relocation target but primary flag is different." + " This [" + this + "], target [" + other + "]";
        return b;
    }
    
    public boolean isRelocationSourceOf(ShardRouting other) {
        boolean b = this.allocationId != null
            && other.allocationId != null
            && other.state == ShardRoutingState.INITIALIZING
            && other.allocationId.getId().equals(this.allocationId.getRelocationId());
        assert b == false || this.state == ShardRoutingState.RELOCATING
            : "ShardRouting is a relocation source but shard state isn't relocating. This [" + this + "], other [" + other + "]";
        assert b == false || this.allocationId.getId().equals(other.allocationId.getRelocationId())
            : "ShardRouting is a relocation source but the allocation id isn't equal to other.allocationId.getRelocationId."
                + " This ["
                + this
                + "], other ["