[Backport] Opportunistic Striping

[Ghatage]

If you have a very small cluster, 3 bookies, you must use 2-2-2 as replication parameters in order to guarantee durability and tolerate the failure of at least one bookie.
With this situation you cannot leverage the striping feature of BookKeeper, when ensembleSize > writeQuorumSize.

With striping you can distribute your data among all of the bookies, and use better the available disk space.
You can also exploit the ability to write to/read from more disks (bookies) in parallel, achieving better overall performances.

With this change we introduce a new client option "opportunistic striping", that basically tells to the BK client to use as much bookies as configured in the ensembleSize parameter in the best case scenario, and to use less and less bookies, up to the configured writeQuorumSize.

• New ClientConfiguration option "opportunisticStriping"
• in case of opportunisticStriping the client is allowed to use less bookies than the requested ensemble size, up to writeQuorumSize
• add test cases

Reviewers: Nicolò Boschi boschi1997@gmail.com, Anup Ghatage ghatage@apache.org

This closes #2493 from eolivelli/fix/bp-43-impl-auto-striping

Descriptions of the changes in this PR:

Motivation

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Changes

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Master Issue: #

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[eolivelli]

LGTM
thank you for backporting my patch !

[Ghatage]

@eolivelli doesn't GH Actions run for previous branches?

[eolivelli]

@Ghatage maybe you are right.
We have to investigate

[Ghatage]

It seems so.

We might have to make changes to the github workflow yml files. I'll check up if we can do this in some centralized place so that we can toggle it for only the branches / releases which are not EOL.