Purpose
=======
Improve sponsor management in order to transform it into a real business
document allowing to communicate with them directly.
Specifications
==============
Add integration with mailgateway and activities through mail.thread and
mail.activity.mixin inheritance.
Improve sponsor views: add a real form view and add a small kanban view
displaying some partner / sponsor information.
Task ID 2119333
PR #40949
Stéphane Debauche
b8966ac660