Feature to create a new workflow from existing workflows

Combine the whole thing.

```
biox concat -w qc_workflow.yml,reseq_workflow.yml -o my_combined_workflow.yml
```

Also have the ability to select/omit rules

```
```
biox concat -w qc_workflow.yml,reseq_workflow.yml --select_rules rule1,rule2,rule3 -o my_combined_workflow.yml
``` 