WIP: Implement service account authentication with pulsar

[martin31821]

Fixes #125

Motivation

Currently, it is not possible to authenticate to a pulsar cluster with OIDC / Kubernetes Service Account tokens. This PR adds support for it

Modifications

• Added a reference to a service account as option of the k8s CRD

Verifying this change

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

This change ~~added~~ will add 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

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