Add the ability to use Azure Workload Identities

[karlschriek]

Description
Adds the ability to use Azure Workload Identities by setting "useWorkloadIdentity": true. Bumps the adal version to 0.9.20 in order to use the new adal.NewServicePrincipalTokenFromFederatedToken function.

Fixes #2724 (although note, it does not deal with ensuring that the refreshed token is read from disk)

Checklist

No I haven't done these things yet. Does someone want to point me to where I go to do this?

• Unit tests updated
• End user documentation updated

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: karlschriek / name: Karl Schriek (8def50e, c213dd7)

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[k8s-ci-robot]

@karlschriek: PR needs rebase.

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/lifecycle stale

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/lifecycle rotten

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/close

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@k8s-triage-robot: Closed this PR.

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/close

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[cgroschupp]

/reopen

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[karlschriek]

No need to reopen this. Has been superseded by #3111