Programmatic access to file syncing services

<!--HTML-->Ganga is a python API for submitting jobs to distributed computing systems. When a user submits processing jobs to a Grid or a Cloud resource, these jobs will often depend on input as well as producing output. To make the job gain access to the input and how to get easy access to the output afterwards is often a challenge. Within the Ganga framework, we have implemented an abstraction layer for file access. In addition to the traditionally used grid storage solutions, it is now possible to retrieve and store files to Google Drive and ownCloud implementations. The latter, which also provides access to CERNbox, is provided via WebDav access that also opens up many other possibilities. Specific use case will be discussed as well as the wider issues related to authentication.