Add support for Workload Identity authentication in azure-security-keyvault-jca

[thomob]

Description

As continuation of work provided in PR #47051, this PR adds the option of using Workload identity authentication in AKS via a federated token file to the azure-security-keyvault-jca module.

All SDK Contribution checklist:

• The pull request does not introduce [breaking changes]
• CHANGELOG is updated for new features, bug fixes or other significant changes.
• I have read the contribution guidelines.

General Guidelines and Best Practices

• Title of the pull request is clear and informative.
• There are a small number of commits, each of which have an informative message. This means that previously merged commits do not appear in the history of the PR. For more information on cleaning up the commits in your PR, see this page.

Testing Guidelines

• Pull request includes test coverage for the included changes.

[github-actions]

Thank you for your contribution @thomob! We will review the pull request and get back to you soon.

[rujche]

Hi, @thomob , thank you so much for your contribution! We will review it soon.

[rujche]

Hi, @g2vinay Could you please help to review this PR? Maybe merge current PR and your PR (#47051) into one PR? Since your PR contains more update about README, how about taking the valuable content form current PR into your PR and then close current PR?