repo job improvements and blob store job

If you POST an existing/duplicate repo via Nexus 3.38.x API it breaks Nexus completely and requires a restart of the pod. These changes allow for an API GET to check if the repo already exists, and if so, performs a PUT instead of a POST. This will also allow for config updates to a repo.

Also, since Iron Bank uses s3 blob storage for their repos created via this chart, we've added a new section for creating a blob store via the chart in the same GET/POST/PUT fashion as the repo updates included here.