Add service_area_name property to output of /budget/history/bureau/ endpoint

[jimtyhurst]

Expected behavior:

Whenever a "code" property appears in API output, the response should also include the corresponding "name" property. The Bureau endpoint response has the service_area_code, so a user expects the response to also have a service_area_name property in the same way that the response has bureau_code and bureau_name properties in the response.

Actual behavior

The Bureau endpoint does not have a service_area_name property.

Background info

The History table has code/name properties for all of the properties, except for "service area". So we need to join the budget_app_budgethistory table to the budget_app_lookupcode table to use the service_area_code in the budget_app_budgethistory table to get the description in the budget_app_lookupcode table.

This is a follow-up to the endpoint developed as a solution to Issue #76.