Support using certificates for Azure Key vault.

[sp98]

Is this a BUG REPORT or FEATURE REQUEST?:
FEATURE REQUEST

What happened:
As of now, the azure key vault client can be created using the ClientID and ClientSecret. The recommended way of creating the client is using a certificate.

What you expected to happen:
Create azure key vault client using certificate. Use the NewServicePrincipalTokenFromCertificate function to generate the token using certificate.

How to reproduce it (as minimally and precisely as possible):
N/A

Anything else we need to know?:
N/A

Environment:

• Container Orchestrator and version:
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

[sp98]

@adityadani

I'm from the Rook team.
I would like to take this up and work on it. Just wanted to check if you are still accepting contributions.

[adityadani]

@sp98 Yes feel free to send out a PR and we will review it. cc @dahuang-purestorage