Update /finance/budgets POST and PUT APIs

Purpose/Overview:
To support UIF-212, some adjustments to /finance/budgets API have to be made.

Requirements/Scope:

1. Create schema that will contain budget information and expenseClasses - list of objects(expenseClassId, status)
2. Update POST /finance/budgets and PUT /finance/budgets/id APIs:
   • to use new schema
   • to create(POST, PUT use POST /finanse-storage/budget-expense-classes), update(PUT use PUT /finanse-storage/budget-expense-classes/id), delete(PUT use DELETE /finanse-storage/budget-expense-classes/id) budget-expense-classes recorders based on expenseClasses

Approach:
New schema can be a composite like CompositePurchaseOrder or an extension of budget schema

Acceptance criteria:

• schema created
• samples added
• APIs updated
• Unit tests updated
• API tests updated