Support create token with headers

[coderzc]

trafficstars

Master Issue: #

Motivation

Currently, the tool that generates the token cannot attach headers. We should support it. For example, it makes sense to attach a kid field for JWKS.

Modifications

Support create token with headers

Verifying this change

• [x] Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Documentation

Check the box below.

Need to update docs?

• [ ] doc-required

  (If you need help on updating docs, create a doc issue)

• [x] no-need-doc

  (Please explain why)

• [ ] doc

  (If this PR contains doc changes)