…ngs (elastic#82819)

Today the setting indices.recovery.max_bytes_per_sec defaults to different 
values depending on the node roles, the JVM version and the system total 
memory that can be detected.

The current logic to set the default value can be summarized as:

    40 MB for non-data nodes
    40 MB for data nodes that runs on a JVM version < 14
    40 MB for data nodes that have one of the data_hot, data_warm, data_content or data roles

Nodes with only data_cold and/or data_frozen roles as data roles have a 
default value that depends of the available memory:

    with ≤ 4 GB of available memory, the default is 40 MB
    with more than 4 GB and less or equal to 8 GB, the default is 60 MB
    with more than 8 GB and less or equal to 16 GB, the default is 90 MB
    with more than 16 GB and less or equal to 32 GB, the default is 125 MB
    and above 32 GB, the default is 250 MB

While those defaults served us well, we want to evaluate if we can define 
more appropriate defaults if Elasticsearch were to know better the limits 
(or properties) of the hardware it is running on - something that Elasticsearch 
cannot extract by itself but can derive from settings that are provided at startup.

This pull request introduces the following new node settings:

    node.bandwidth.recovery.network
    node.bandwidth.recovery.disk.read
    node.bandwidth.recovery.disk.write

Those settings are not dynamic and must be set before the node starts. 
When they are set Elasticsearch detects the minimum available bandwidth 
among the network, disk read and disk write available bandwidths and computes 
a maximum bytes per seconds limit that will be a fraction of the min. available 
bandwidth. By default 40% of the min. bandwidth is used but that can be 
dynamically configured by an operator 
(using the node.bandwidth.recovery.operator.factor setting) or by the user 
directly (using a different setting node.bandwidth.recovery.factor).

The limit computed from available bandwidths is then compared to pre existing 
limitations like the one set through the indices.recovery.max_bytes_per_sec setting 
or the one that is computed by Elasticsearch from the node's physical memory 
on dedicated cold/frozen nodes. Elasticsearch will try to use the highest possible 
limit among those values, while not exceeding an overcommit ratio that is also 
defined through a node setting 
(see node.bandwidth.recovery.operator.factor.max_overcommit).

This overcommit ratio is here to prevent the rate limit to be set to a value that is 
greater than 100 times (by default) the minimum available bandwidth.