[FEATURE] Improve error messages that come from `jsonschema`

[Stranger6667]

It is unclear why the input schema is invalid from the jsonschema's error output:

jsonschema.exceptions.ValidationError: False is not of type 'array'

Failed validating 'type' in schema[0]['properties']['required']:
    {'items': {'type': 'string'},
     'minItems': 1,
     'type': 'array',
     'uniqueItems': True}

On instance['required']:
    False

Similarly, the jsonschema error output is confusing when the schema has HTTP status codes as numbers (they should be strings).

Related issues:

• #610
• #513
• #1140

Update: The first step could be applying the right ordering to the best_match function from jsonschema. Other JSON Schema libraries are likely to have similar error structures for oneOf cases. See editor.swagger.io

[Stranger6667]

TypeError related to the usage of numeric HTTP codes should be resolved by #1294