cephfs: volumes are now created for separate ceph users with limited access to fs

Uses a slightly modified version of https://github.com/kubernetes-incubator/external-storage/blob/master/ceph/cephfs/cephfs_provisioner/cephfs_provisioner.py
This should be rewritten properly in Go, but for it works for now - for demonstration purposes

TODO:
* readOnly is not taken into account
* controllerServer.DeleteVolume does nothing

deploy/cephfs/docker/Dockerfile

@@ -5,9 +5,10 @@ LABEL description="CephFS CSI Plugin"
 ENV CEPH_VERSION "luminous"
 
 RUN apt-get update && \
-    apt-get install -y ceph-fuse attr && \
-     apt-get autoremove
+    apt-get install -y ceph-common ceph-fuse && \
+    rm -rf /var/lib/apt/lists/*
 
 COPY cephfsplugin /cephfsplugin
-RUN chmod +x /cephfsplugin
+COPY cephfs_provisioner.py /cephfs_provisioner.py
+RUN chmod +x /cephfsplugin && chmod +x /cephfs_provisioner.py
 ENTRYPOINT ["/cephfsplugin"]