Feature Request: Persistent table upload

Some services (ESA's various services, CADC) benefit from allowing users to upload tables and have them persist on the server. That is not presently supported by any VO protocols (right?), but is a useful feature to have as an extension here.

The issue names no files, tests, or entry points. Start by determining how pyVO handles table uploads and which VO protocol or server-side extension would support persistence; done means users can upload tables and retrieve them later from the server.

Written by the indexing model from the issue text.