Feature/zenko 1402 move data backends

[dora-korpar]

Beginning the work of moving the data backends to Arsenal.
This PR includes the external backend clients, the necessary supporting functions, and the existing unit tests for both of those.
Most files have simply been copied over (with adjusted requirements). The only code changes beyond requirements have been to getVault.js, which was copied over from vault.js (https://github.com/scality/cloudserver/blob/development/8.1/lib/auth/vault.js) in CloudServer. In order to circumvent the problem of assuming the use of the CloudServer config, the code was wrapped in a function.
The other change is that a config parameter was introduced to several client function, as they too require the CloudServer config.

[bert-e]

Hello dora-korpar,

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[bert-e]

Waiting for approval

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[dora-korpar]

@bert-e reset

[bert-e]

Reset complete

I have successfully deleted this pull request's integration branches.

[bert-e]

Waiting for approval

The following approvals are needed before I can proceed with the merge:

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[vrancurel]

We introduce here a circular dependency: only cloudserver shall be able to have vaultclient in its package.json. The vaultclient lib instance shall be passed from cloudserver to Arsenal (just like sproxydclient and bucketclient)

will be done potentially in 2 steps

[vrancurel]

where are we now ?

[dora-korpar]

The vaultclient dependency was removed, and this is ready to go, there are just a few tests failing in CloudServer that I need to verify before merging this

[bert-e]

Waiting for approval

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• the author

• 2 peers

Peer approvals must include at least 1 approval from the following list:

• @rahulreddy

• @bennettbuchanan

• @rachedbenmustapha

[dora-korpar]

@bert-e approve

[bert-e]

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The changeset will be merged in:

• ✔️ development/8.1

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• development/6.4
• development/7.4
• development/8.0

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[bert-e]

I have successfully merged the changeset of this pull request
into targetted development branches:

• ✔️ development/8.1

The following branches have NOT changed:

• development/6.4
• development/7.4
• development/8.0

Please check the status of the associated issue ZENKO-1402.

Goodbye dora-korpar.