Allow Google Cloud storage backend to be used

[simonjohansson]

Topic \o/

[jhunt]

Is there a particular advantage to using Google Cloud Storage for Vault backends?

[simonjohansson]

Well, its less for me to maintain :)

[jhunt]

Can you resolve these conflicts?

[jhunt]

I apparently don't know how to use the GH conflict resolver. :/

[simonjohansson]

Sure, ill take a look!

[simonjohansson]

Rebased to master.

[jhunt]

Bloody hell. All these PRs conflict with each other. Can you take another crack now that the other PR was merged?

[simonjohansson]

@jhunt should be mergable now!

[jhunt]

Thanks!