#663 - refactor: moved MigrationController

BudgetMasterServer/src/main/java/de/deadlocker8/budgetmaster/controller/MigrationController.java → BudgetMasterServer/src/main/java/de/deadlocker8/budgetmaster/migration/MigrationController.java

-package de.deadlocker8.budgetmaster.controller;
+package de.deadlocker8.budgetmaster.migration;
 
+import de.deadlocker8.budgetmaster.controller.BaseController;
 import de.deadlocker8.budgetmaster.settings.SettingsService;
 import de.deadlocker8.budgetmaster.utils.Mappings;
 import org.springframework.beans.factory.annotation.Autowired;