Improve container credentials retrieval using workflow compute environment

[pditommaso]

Wave retrieves the container credentials to be used, querying Tower credentials for container-reg provider and looking for a matching registry name.

This is convenient for users that rely on registries such as Docker or Quay. However, it can be suboptimal for users that store container images in the cloud registry provided by the cloud vendor associated with by the pipeline execution.

The goal of this issue is to extend the credentials retrieval mechanism in such a way that when there isn't a credentials match for the required repositories, the system fallbacks to the crendianls associated with the compute environment used by the pipeline execution.

The above approach should take place only when the container repository is hosted in the same platform where the pipeline executed e.g. AWS ECR and the execution platform is AWS Batch