Add support to customize the container image workload

[avisiedo]

• Add WORKLOAD_IMAGE environment variable to customize the container image workload.
• The operator customize the workload based on the value of this variable; if unset or empty, then the default container image used for the workload will be quay.io/freeipa/freeipa-openshift-container:freeipa-server.

Example:

WORKLOAD_IMAGE="quay.io/avisied0/freeipa-openshift-container:dev-f47400e" make run

This is a Red Hat marketplace requirement: https://redhat-connect.gitbook.io/certified-operator-guide/troubleshooting-and-resources/offline-enabled-operators#golang-operators

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: avisiedo

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[avisiedo]

I have missed a few things:

• The workload was not passed to the Statefulset object.
• The entrypoint was not updated for the fresh images.
• Update unit tests for the above.
• Clean-ups.

PR updated.

[avisiedo]

After the changes into the notes, the PR can be merged.

[avisiedo]

/test unit

[avisiedo]

/test unit

[avisiedo]

/test unit

[avisiedo]

/test unit