mounting scales linearly with the number of compute nodes

[JohnGarbutt]

Currently we do the mount in a serial loop of ssh requests. This gets very slow with large numbers of compute nodes.

We should move to ansible to do the mount on both clients and servers. That way we have a single way to manage concurrent ssh connections.

[JohnGarbutt]

in addition we seem some quite random looking ssh failures. We have tracked down the cause of some failures, but using ansible for all ssh connections would help fix these issues in one place.