Add license and SCM to setup.py

[tsteenbe]

Could you please add a license and source code declaration to the setup.py file?

Currently msal-extensions causes a violation in our OSS check as these license and source code location fields are missing for this package on https://pypi.org/project/msal-extensions/.
Not a Python guy but believe this can be fixed by adding the following to https://github.com/AzureAD/microsoft-authentication-extensions-for-python/blob/dev/setup.py#L16-L35:

license='MIT',
classifiers=[
       'Development Status :: 2 - Pre-Alpha',
       'License :: OSI Approved :: MIT License '
],
project_urls={
        'Source': 'https://github.com/AzureAD/microsoft-authentication-extensions-for-python.git'
},