Add integrations tests and chane unit tests

transaction-service/pom.xml

...src/it/java/cz/muni/fi/obs/ControllerIntegrationTest.java

...uni/fi/obs/rest/TransactionControllerIntegrationTest.java

transaction-service/src/it/resources/initialize_db.sql

...java/cz/muni/fi/obs/controller/TransactionController.java

...ava/cz/muni/fi/obs/data/repository/AccountRepository.java

...cz/muni/fi/obs/data/repository/TransactionRepository.java

...va/cz/muni/fi/obs/facade/TransactionManagementFacade.java

.../main/java/cz/muni/fi/obs/service/TransactionService.java

.../cz/muni/fi/obs/controller/TransactionControllerTest.java

...z/muni/fi/obs/facade/TransactionManagementFacadeTest.java

...java/cz/muni/fi/obs/repository/AccountRepositoryTest.java

.../cz/muni/fi/obs/repository/TransactionRepositoryTest.java

...t/java/cz/muni/fi/obs/service/TransactionServiceTest.java

transaction-service/src/test/resources/application-test.yml

transaction-service/src/test/resources/drop_all.sql

transaction-service/src/test/resources/initialize_db.sql