Implement usage of newly extraced visual features

therefore do not use the one big visual features json,
but for every pictures its own json
it is not yet tested
Merge branch 'master' into use_newly_extracted_visuals

Conflicts:
	src/clustering/visual/combined_clustering.py
Fix bug, forgot to delete a parameter in a method
merge with master, solve conflict
Fix: renaming of variables not ended and empty dict not created
Merge remote-tracking branch 'origin/use_newly_extracted_visuals'

Conflicts:
	src/clustering/visual/combined_clustering.py
Refactor code: Delete deprecated and unused main method
Fix: when loading metadata jsons, check, that file names end on digit (before file ending)