[Doc] how we can use this SDK in a pure python project without Django

[peppelinux]

• [ ] have all the spid_cie_oidc.entity Federation API available
  • [ ] small refactor to handle the absence of django.settings (a simple try/except with a fallback to os.environ ENV values)
• [ ] A brief introduction about how to wrap the classes/funcs views of Authority/Provider/RP in flask or any other framework:
  • [ ] how to monkey patch the django ORM operations to substitute them with some proxy function/class