feat: validate Promise pipelines

[ChunyiLyu]

Context

Workflow pipelines are not validated by Kratix webhook at Promise creation and update. Promises with invalid pipelines are being 'successfully applied by kratix. Users need to look at kratix logs to be able to find out what went wrong.

This story is about adding pipeline validation to our Promise validation webhook to provide faster feedback to our users about what went wrong.

Validation in scope for this issue is about identifying invalid pipelines that will prevent pipeline resources (jobs/rbac objects) being generated. When pipeline resources can be generated and created but pipeline fails to execute, that's not the problem we are trying to tackle here, for example a container that uses private image that cannot be pulled is not a concern for this issue.

Validation should be performed on all workflow types and actions, promise and resources, configure and delete.

Give a Promise with a workflow pipeline
When a container under `spec.containers has no container image or container name
This Promise fail to apply (create and update)

When the spec cannot generated into a Kubernetes Job
This Promise fail to apply (create and update)

When there is an unknown key specified under the pipeline spec
This Promise fail to apply (create and update)

When `spec.volumes` `spec.imagePullSecrets` or `spec.rbac` cannot be parsed by Kratix
This Promise fail to apply (create and update)