Merge branch 'feat/pdf' into 'dev'

pom.xml

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

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

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

src/main/java/NTNU/IDATT1002/utils/CreateUser.java

src/main/java/NTNU/IDATT1002/utils/ImageUtil.java

src/main/java/NTNU/IDATT1002/utils/PdfDocument.java

src/test/java/NTNU/IDATT1002/utils/PdfDocumentTest.java

src/test/java/tmp/test_image_1.jpg

src/test/java/tmp/test_image_2.jpg