Add example for provider config terraform for Azure

[jankaacc]

Description of your changes

Added example for initializing provider terraform for azure tfvars file is used to do that

Fixes #

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[jankaacc]

ediately obvious to me where the values for subscriptionId/tenantId/clientId/clientSecret come from - I assume they are in the azure-secret?

agree, will add this secret above the providerConfig

[jankaacc]

updated

[ytsarev]

@jankaacc can you please sign the CLA before we merge this one?