### 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
/**
     * Writes shard information to {@link StreamOutput} without writing index name and shard id
     *
     * @param out {@link StreamOutput} to write shard information to
     * @throws IOException if something happens during write
     */
    public void writeToThin(StreamOutput out) throws IOException {
        out.writeOptionalString(currentNodeId);
        out.writeOptionalString(relocatingNodeId);
        out.writeBoolean(primary);
        out.writeByte(state.value());
        if (state == ShardRoutingState.UNASSIGNED || state == ShardRoutingState.INITIALIZING) {
            recoverySource.writeTo(out);
        }
        out.writeOptionalWriteable(unassignedInfo);
        if (out.getVersion().onOrAfter(RELOCATION_FAILURE_INFO_VERSION)) {
            relocationFailureInfo.writeTo(out);
        }
        out.writeOptionalWriteable(allocationId);
        if (state == ShardRoutingState.RELOCATING
            || state == ShardRoutingState.INITIALIZING
            || (state == ShardRoutingState.STARTED && out.getVersion().onOrAfter(EXPECTED_SHARD_SIZE_FOR_STARTED_VERSION))) {
            out.writeLong(expectedShardSize);
        }
    }
    @Override
    public void writeTo(StreamOutput out) throws IOException {
        shardId.writeTo(out);
        writeToThin(out);
    }