Add LoadDatabase to load test data into the database

.gitignore

src/main/java/NTNU/IDATT1002/App.java

src/main/java/NTNU/IDATT1002/database/LoadDatabase.java

src/main/java/NTNU/IDATT1002/models/User.java

src/main/java/NTNU/IDATT1002/repository/TagRepository.java

src/main/java/NTNU/IDATT1002/service/ImageAlbumService.java

src/main/java/NTNU/IDATT1002/service/ImageService.java