Allow system to use google cloud storage (buckets)

[raprasad]

Persistent file storage will be needed, including temporarily storing source data as well as longer term storage of metadata. Options include:

• objects (google buckets)
  • best and definitely for any serious system. more work for code updates in rook
  • reference: https://cran.r-project.org/web/packages/googleCloudStorageR/vignettes/googleCloudStorageR.html
• persistent disk (limited, much easier to setup, may be fine fo demos. e.g. (50 gb is $6/month for gce)
  • may be ok for tests
• metadata: store in sql or mongo

When deployed via k8s on gce, any files downloaded or created should use this persistent storage

What scenarios need to be handled?

• Download dataverse metadata as well as source files and save them to a bucket
• Upload a source file and save it to a bucket
• When appropriate, pass references to storage objects between the containers (python, R)
• ???