### 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
/**
     * The shard id.
     */
    public int id() {
        return shardId.id();
    }
    /**
     * The shard id.
     */
    public int getId() {
        return id();
    }
    /**
     * The shard is unassigned (not allocated to any node).
     */
    public boolean unassigned() {
        return state == ShardRoutingState.UNASSIGNED;
    }
    /**
     * The shard is initializing (usually recovering either from peer shard
     * or from gateway).
     */
    public boolean initializing() {
        return state == ShardRoutingState.INITIALIZING;
    }
    /**
     * Returns <code>true</code> iff the this shard is currently
     * {@link ShardRoutingState#STARTED started} or
     * {@link ShardRoutingState#RELOCATING relocating} to another node.
     * Otherwise <code>false</code>