Move to CSI 0.3.0

[gman0]

I already have some code ready, hopefully should be finished by the end of the next week.

[gman0]

@rootfs Ok, I've tested both RBD and CephFS in my 1-VM Ceph cluster so hopefully this should be ready for review. I'll be gradually pushing four PRs to make it easier to track and review:

• PR 1: vendor update to CSI 0.3.0
• PR 2: makefile, manifests, examples, docs
• PR 3: csi-cephfs 0.3.0
• PR 4: csi-rbd 0.3.0 (this is just a version bump for now)

[gman0]

Just FYI, here is the branch with all the prepared changes (i.e. the upcoming 4 PRs together): https://github.com/gman0/ceph-csi/tree/v0.3.0

[gman0]

#61 concluded the upgrade to 0.3.0, I'm closing this issue. Thanks.