Add script that runs parts of a single workflow with different files on different WES implementations

### Motivation

A long-standing goal of the FASP GA4GH group has been to have a federated workflow demo that anyone can run. In this context, a federated workflow means:
1. Multiple compute environments are used for a single computational analysis
2. Different data is analysed in each compute environment
3. A single script drives the analysis using GA4GH standards, where possible

### Goals
1. Automate as much of this task as possible in scripts in this repo
2. Use WES API to control and monitor workflows
3. Use public or synthetic data to make this more accessible for other people to try

### Todo

- [ ] Identify some data (preferably with mirrors in different regions)
- [x] Fix script using DNAstack WES
- [x] Write script using ELIXIR WES
- [x] Write script using Seven Bridges WES
- [ ] Write single script calling DNAstack, WES, SB scripts on different subsets of files