1709 category api
Description
ApplicationApiImpl will be divided into separate classes to avoid LongClass which is part of codesmell. In this MR, Category page related codes are separated.
Screenshots
Technical details
An interface CategoryApi is introduced. CategoryApiImpl implements this interface. A class ApplicationDataManager is introduced which manages some common operation related to Application object.
Tests
Issues
backlog/-/issues/1709: Subtask: backlog/-/work_items/1745