Draft: Feat/OIDC passthrough auth

[Mberga14]

Description

Related to #346

Motivation and Context

Enabling support for google access tokens, enabling multi user support if tableau is also secured behind google SSO

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (please describe):

How Has This Been Tested?

Built the image with my changes and tested against LLM tooling that passes through google oauth, connected to a google backed tableau instance

Related Issues

#346

Checklist

• I have updated the version in the package.json file by using npm run version. For example,
  use npm run version:patch for a patch version bump.
• I have made any necessary changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have documented any breaking changes in the PR description. For example, renaming a config
  environment variable or changing its default value.

Contributor Agreement

By submitting this pull request, I confirm that:

• I have read the CONTRIBUTING guidelines for this project and followed
  its Contribution Checklist.

[salesforce-cla]

Thanks for the contribution! Before we can merge this, we need @Mberga14 to sign the Salesforce Inc. Contributor License Agreement.