We limit the number of concurrent blob downloads per node and per recovery, but if a user configures too many concurrent recoveries they may run out of per-node download permits which yields the following message:

> Unable to acquire permit to use snapshot files during recovery, this recovery will recover index files from the source node. Ensure snapshot files can be used during recovery by setting [indices.recovery.max_concurrent_snapshot_file_downloads] to be no greater than [25]

The `[25]` here is wrong, the 25 permits are shared across all inbound recoveries so we should divide the suggested value by `cluster.routing.allocation.node_concurrent_incoming_recoveries`. In extreme cases the user may have configured so many concurrent recoveries that the only reasonable limit is zero, and in that case we should suggest setting `indices.recovery.use_snapshots: false` instead.


server/src/main/java/org/elasticsearch/indices/recovery/RecoverySettings.java
* i.e., local node is not yet known on remote node, remote shard not yet started etc.
     */
    public static final Setting<TimeValue> INDICES_RECOVERY_RETRY_DELAY_STATE_SYNC_SETTING = Setting.positiveTimeSetting(
        "indices.recovery.retry_delay_state_sync",
        TimeValue.timeValueMillis(500),
        Property.Dynamic,
        Property.NodeScope
    );
    
    public static final Setting<TimeValue> INDICES_RECOVERY_RETRY_DELAY_NETWORK_SETTING = Setting.positiveTimeSetting(
        "indices.recovery.retry_delay_network",
        TimeValue.timeValueSeconds(5),
        Property.Dynamic,
        Property.NodeScope
    );
    
    public static final Setting<TimeValue> INDICES_RECOVERY_INTERNAL_ACTION_TIMEOUT_SETTING = Setting.positiveTimeSetting(
        "indices.recovery.internal_action_timeout",
        TimeValue.timeValueMinutes(15),
        Property.Dynamic,
        Property.NodeScope
    );
    
    public static final Setting<TimeValue> INDICES_RECOVERY_INTERNAL_ACTION_RETRY_TIMEOUT_SETTING = Setting.positiveTimeSetting(
        "indices.recovery.internal_action_retry_timeout",
        TimeValue.timeValueMinutes(1),
        Property.Dynamic,
        Property.NodeScope
    );
    /**