[Python] Option to skip client validations

[ghost]

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
• Filed the PR against the correct branch: 3.0.0 branch for changes related to OpenAPI spec 3.0. Default: master.
• Copied the technical committee to review the pull request if your PR is targeting a particular programming language.

Description of the PR

• Adds option to skip all client-side validations for python client
• Option to disable validation in the API clients #5530

[HugoMario]

Thanks for this PR @slash-arun

can you please fix failing tests, such as:

Traceback (most recent call last):
  File "/home/travis/build/swagger-api/swagger-codegen/samples/client/petstore/python/tests/test_enum_arrays.py", line 157, in test_equals
    self.assertEqual(fish1, fish2)
AssertionError: {'array_enum': ['fish'], 'just_symbol': '$'} != {'array_enum': ['fish'], 'just_symbol': '$'}

in order to merge them?

[ghost]

@HugoMario Sorry for leaving this PR hanging, I was caught up with something else. I will fix these asap

[ghost]

@HugoMario @kenjones-cisco @frantuma This PR is ready for review. Please take a look.

[HugoMario]

thanks a lot @slash-arun, this LGTM but would like also someone else review

[ghost]

Sure @HugoMario , let me know if I should CC anyone else in particular. I already cc'd kenjones as per the document.

[ghost]

LGTM 👍

[HugoMario]

please build

[HugoMario]

it seems the source repo was removed, i'm going to migrate changes to another PR in order to merge this