Add Dockstore CLI and dependencies to a CGCloud created VM

[briandoconnor]

This will workflow steps to call Dockstore-based tools.

For the dependencies see:

https://github.com/ga4gh/dockstore/wiki/Dockstore-New-Developer-Tutorial

[hannes-ucsc]

@briandoconnor, to clarify, is this ticket about installing the Dockstore client on the nodes of a CGCloud-provisioned Toil cluster such that Toil workflows can invoke Dockstore-registered Docker images?