Add check that all stage IDs / inputs are valid against the specified app / workflow to run

[jethror1]

If invalid inputs / stages are included it gives unhelpful errors like this:

Traceback (most recent call last):
  File "run_workflows/run_workflows.py", line 649, in <module>
    main()
  File "run_workflows/run_workflows.py", line 604, in main
    job_outputs_dict = dx_execute.call_per_run(
  File "/home/dnanexus/run_workflows/utils/dx_requests.py", line 565, in call_per_run
    input_dict = ManageDict().check_input_classes(
  File "/home/dnanexus/run_workflows/utils/manage_dict.py", line 785, in check_input_classes
    expected_class = input_details.get('class')

Would be better to check up front that everything in the config is valid against what is going to be run