👔(backend) add Organization model

We introduce the Organization model has a "hat" for all
users and team.

Each User must have a "default" organization.
Each Team must have an organization.

When a User creates a new Team, the team is linked to their
default Organization.

For now the Organization should not be visible to end users
this is a purely technical aspect as it.

The models are also adding a permission to allow User to edit
an Organization, but for now there are no endpoints for that.

Next steps:
- Add an Organization to each User and Team on all environments
  to mark Organization as mandatory in database.
- Add scope to Organization to list the Service Provider list
  allowed for a User in an Organization.
- Add endpoints + frontend to manage Organization's scopes

src/backend/.pylintrc

@@ -363,7 +363,8 @@ name-group=
 
 # Regular expression which should only match function or class names that do
 # not require a docstring.
-no-docstring-rgx=^_
+# Ignore: private stuff and `Params` class from FactoryBoy
+no-docstring-rgx=(^_|^Params$)
 
 # List of decorators that produce properties, such as abc.abstractproperty. Add
 # to this list to register other decorators that produce valid properties.