fix: pass admintools.additionalEnv to create-store and manage-schema containers (#865)

[jiechenz]

What was changed

This change added additionalEnv, additionalEnvSecretName, and additionalEnvConfigMapName support to the create-*-store and manage-schema-*-store init containers in server-job.yaml.

Before the change these were only passed to the create-*-namespace containers.

Updated unit tests to assert that additional env are present on all init container types.

Why?

Bug fix: Environment variables set via admintools.additionalEnv are not inherited by the create-default-store, setup-default-store, and update-default-store init containers.

Checklist

1. Closes [Bug] admintools.additionalEnv not being passed to create/manage-schema containers #865

2. How was this tested:
   Updated helm unittest test case "includes additional environment variables" in server_job_test.yaml to cover all init container types

3. Any docs updates needed?
   Bug fix, README already covers this feature.