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
public static final Setting<Double> NODE_BANDWIDTH_RECOVERY_OPERATOR_FACTOR_READ_SETTING = operatorFactorSetting(
        "node.bandwidth.recovery.operator.factor.read"
    );
    public static final Setting<Double> NODE_BANDWIDTH_RECOVERY_OPERATOR_FACTOR_MAX_OVERCOMMIT_SETTING = Setting.doubleSetting(
        "node.bandwidth.recovery.operator.factor.max_overcommit",
        100d, 
        1d,
        Double.MAX_VALUE,
        Property.NodeScope,
        Property.OperatorDynamic
    );
    public static final Setting<Double> NODE_BANDWIDTH_RECOVERY_FACTOR_WRITE_SETTING = factorSetting(
        "node.bandwidth.recovery.factor.write",
        NODE_BANDWIDTH_RECOVERY_OPERATOR_FACTOR_WRITE_SETTING
    );
    public static final Setting<Double> NODE_BANDWIDTH_RECOVERY_FACTOR_READ_SETTING = factorSetting(
        "node.bandwidth.recovery.factor.read",
        NODE_BANDWIDTH_RECOVERY_OPERATOR_FACTOR_READ_SETTING
    );
    static final List<Setting<?>> NODE_BANDWIDTH_RECOVERY_SETTINGS = List.of(
        NODE_BANDWIDTH_RECOVERY_NETWORK_SETTING,
        NODE_BANDWIDTH_RECOVERY_DISK_READ_SETTING,
        NODE_BANDWIDTH_RECOVERY_DISK_WRITE_SETTING
    );
    /**
     * Bandwidth settings have a default value of -1 (meaning that they are undefined) or a value in (0, Long.MAX_VALUE).
     */
    private static Setting<ByteSizeValue> bandwidthSetting(String key) {
        return new Setting<>(key, ByteSizeValue.MINUS_ONE.getStringRep(), s -> {
            final ByteSizeValue value = ByteSizeValue.parseBytesSizeValue(s, key);