Updating JobBinaries to use proxy for Swift access

Changes
* refactoring get_raw_binary to accept proxy configs
* refactoring get_raw_data to use proxy Swift connection when necessary
* adding function to get a Swift Connection object from proxy user
* refactoring upload_job_files_to_hdfs and upload_job_files to use proxy
  user when necessary
* changing JobBinary JSON schema to allow blank username/password if
  proxy domains are being used
* adding function to get the Swift public endpoint for the current
  project
* adding test for JobBinary creation without credentials

Partial-implements: blueprint edp-swift-trust-authentication
Change-Id: I02e76016194fbbb62b8ab7b304eecc53d580a79c
Merge "Updating JobBinaries to use proxy for Swift access"