Describe the enhancement: Relax content-type restrictions

Describe a specific use case for the enhancement or feature: Currently the GCS Input imposes a strict content-type restrictions for the blobs it downloads. While this is good in theory, it creates a lot of restrictions for users when the blobs do not have the proper content-type automatically assigned in its metadata thereby getting rejected in the download process. This becomes even more restrictive when the end user does not have access to the containers they are pulling from and are unable to change the meta-data info in any way.

The goal is to figure out a way in which these content-type restrictions can be relaxed without introducing majors errors in the ingestion process.