Provide a prefix filter for the Bucket spec

[rmakram-ims]

I would like to use the same S3 bucket accross multiple projects and only give access to a specific prefix for each one of the projects. Currently, the bucket controller downloads the whole contents of the bucket and the filtering is done on the HelmChart spec or on the Ignore option, but this is only applied after all the contents of the bucket have been downloaded. Adding a prefix filter would also make the process more efficient. Thank you

[stefanprodan]

Currently, the bucket controller downloads the whole contents of the bucket and the filtering is done on the HelmChart spec or on the Ignore option, but this is only applied after all the contents of the bucket have been downloaded.

We plan to apply the ignore filter before downloading the files, this way we don't need a prefix filter field.