Add flat label list tab

[lehecht]

• Add tests in VideoAnnotationControllerTest
• Add tests in ImageAnnotationControllerTest
• Add project largo flat tab view
• Update annotation count after swapping/deleting labels
• Update label highlighting in LabelTab (and vice versa)

Closes #170.

[mzur]

A nice improvement 👍 Two main comments:

• The labels still are not ordered alphabetically. The volume endpoint sorts them correctly but the ordering is lost in the frontend. In the project endpoint the orderBy() is missing, too. You should add tests for this.

• One thing I completely forgot about: Annotation sessions. If there is an annotation session that e.g. hides old annotations, these are still counted in the flat labels tab. When clicking on one of these labels, it says "no annotations exist". Adding the annotation session filter to the volume queries should be straight forward. Here is an example (also observe the edge case included there). Also add tests for this. Annotation sessions are ignored in project largo so there is no need to change anything there.

[mzur]

All good, thanks! Just one npm run prod was missing. I also updated the Largo manual article.