[bug-767]: karavictl generate token outputs yaml

[atye]

Description

karavictl generate token outputs yaml that can be applied to k8s without any processing.

# karavictl generate token --tenant PancakeGroup --admin-token <file> --insecure --addr <address>
apiVersion: v1
data:
  access: ZXlKaGJHY2lPaUpJVXpJMU5pSXNJblI1Y0NJNklrcFhWQ0o5LmV5SmhkV1FpT2lKamMyMGlMQ0psZUhBaU9qRTJPREl3T1RBM09EVXNJbWR5YjNWd0lqb2lVR0Z1WTJGclpVZHliM1Z3SWl3aWFYTnpJam9pWTI5dExtUmxiR3d1WTNOdElpd2ljbTlzWlhNaU9pSkRVMGxUYVd4MlpYSXNRMU5KUjI5c1pDSXNJbk4xWWlJNkltTnpiUzEwWlc1aGJuUWlmUS44dG9mdGg0M2V1ZU8wcDY4dEp3MS0tVXVDYXlrMXhuNXhkekRXNFJSMXpj
  refresh: ZXlKaGJHY2lPaUpJVXpJMU5pSXNJblI1Y0NJNklrcFhWQ0o5LmV5SmhkV1FpT2lKamMyMGlMQ0psZUhBaU9qRTJPRFEyT0RJM01qVXNJbWR5YjNWd0lqb2lVR0Z1WTJGclpVZHliM1Z3SWl3aWFYTnpJam9pWTI5dExtUmxiR3d1WTNOdElpd2ljbTlzWlhNaU9pSkRVMGxUYVd4MlpYSXNRMU5KUjI5c1pDSXNJbk4xWWlJNkltTnpiUzEwWlc1aGJuUWlmUS53SzlXYlZ3YVlKcEFOamxqcnh2bjhkcE5tOGVXR2Z0RUhsQmFoVVd0bkhR
kind: Secret
metadata:
  creationTimestamp: null
  name: proxy-authz-tokens
type: Opaque

Also removes superfluous response.writeheader calls.

GitHub Issues

List the GitHub issues impacted by this PR:

GitHub Issue #
dell/csm#767

Checklist:

• I have performed a self-review of my own code to ensure there are no formatting, vetting, linting, or security issues
• I have verified that new and existing unit tests pass locally with my changes
• I have not allowed coverage numbers to degenerate
• I have maintained at least 90% code coverage
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• Backward compatibility is not broken

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Please also list any relevant details for your test configuration

Existing unit tests and manual tests.

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run e2e test

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e2e pass