Add integration test for AcademyAdminController::CR(U)D

[dewarim]

Add an exemplary integration test for academy administration (Create, Read, (Update) Delete).
This test should be simple enough so it can be used as a template for the other admin pages.

Note: the complete integration test needs to be customized since some objects have rather complex create/update logic (for example, an Academy has multi-select fields for Guilds, which make this a little more difficult than the TownAdminController).