feat: added support for fetching access token from oauth server

[sbansla]

Fixes

Added support for fetching access token from OAuth server by passing clientId and clientSecret.
Pending: update readme

Checklist

• I acknowledge that all my contributions will be made under the project's license
• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the Contribution Guidelines and my PR follows them
• I have titled the PR appropriately
• I have updated my branch with the main branch
• I have added tests that prove my fix is effective or that my feature works
• I have added the necessary documentation about the functionality in the appropriate .md file
• I have added inline documentation to the code I modified

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[sonarcloud]

Quality Gate failed

Failed conditions
0.0% Coverage on New Code (required ≥ 80%)
8.4% Duplication on New Code (required ≤ 3%)
E Reliability Rating on New Code (required ≥ A)

See analysis details on SonarCloud

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[sbansla]

For testing purpose this has been fixed, We need to fetch audience and grantType from open api specs.