Document budgets
Requires frontend#1537 (closed)
A new Budgets section, between Secrets and Training, should be used to document the new budgets.
An overview page should explain what budgets and budget entries are, and how to access them from the frontend, with screenshots of the budget list and details views.
A warning at the very top of this page can note that this is an EE-only feature.
In the existing rights documentation, a new Budget access section should document the permissions for budgets.