minor formatting
applied formatter
added first batch of methods, 'getting files feeds'
added serializer test
more test api aligned
added serialized for files and folders, removed old payload generation
fixed imports
added comment serializer
integrated with person serializer
fixed comment content serialization
cleaned up old comment payload code
added moderation serializer, removed transformers and templates
fixed tests, regenerated mock data
Merge pull request #1487 from LorenzoBoccaccia/update-file-service

[Fixed] FileService uses serializer for all operations