Fix scoring endpoint HTTP behavior

[algattik]

1. Scoring endpoint should return json, not stringified json

curl -H "Authorization: Bearer $token" $scoringUri \
  -d '{"data":[[1,2,3,4,5,6,7,8,9,10],[10,9,8,7,6,5,4,3,2,1]]}' \
  -H Content-type:application/json

Returns:

"{\"result\": [5113.099642122809, 3713.6329271385334]}"

Expected:

{"result": [5113.099642122809, 3713.6329271385334]}

Probably we should avoid json.dumps() in:

MLOpsPython/code/scoring/score.py

Line 46 in 41ea9b7

return json.dumps({"result": result.tolist()})

2. Scoring endpoint should not return 200 in case of error

Exceptions are swallowed at

MLOpsPython/code/scoring/score.py

Line 47 in 41ea9b7

except Exception as e:

The code should not only return the error message but also set an appropriate HTTP return code.