Specific exceptions for key errors (missing params), other ingestion format errors

[davidlougheed]

Ex. when param is mistyped:

Traceback (most recent call last):
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/app.py", line 2463, in __call__
    return self.wsgi_app(environ, start_response)
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/app.py", line 2449, in wsgi_app
    response = self.handle_exception(e)
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/app.py", line 1866, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/app.py", line 2446, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/app.py", line 1951, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/app.py", line 1820, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/_compat.py", line 39, in reraise
    raise value
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/app.py", line 1949, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/flask/app.py", line 1935, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/dlougheed/git/chord_variant_service/chord_variant_service/ingest.py", line 36, in ingest
    workflow_metadata["inputs"])
  File "/home/dlougheed/git/chord_variant_service/env/lib/python3.6/site-packages/chord_lib/ingestion.py", line 63, in make_output_params
    workflow_params[namespaced_input(workflow_id, input_spec["id"])])
KeyError: 'vcf_gz.vcf_gz_file'