Doc: add examples for GCS object storage
Add examples for using GCS for object storage.
Expand upon exising documentation to cover the use of GCS as opposed to S3, and narrow down the number of copy-pasted examples.
Closes #712 (closed)
[ci skip]
NOTE: This explicitly does not cover GCS usages for backup/restore bucket, as this is currently not supported due to the use of s3cmd
for the scripting.
Edited by Jason Plum