* refactors documents and file upload to be distributed into different subfolders, depending on the type of document (InterventionDocument, RevocationDocument, ...)
* refactors Document model into AbstractDocument
* subclasses RevocationDocument, InterventionDocument, COmpensationDocument, EmaDocument and EcoAccountDocument from AbstractDocument to provide proper functionality for each
* adds new specialized routes for each new document type (opening, removing)
* drops generic get and remove routes for documents
* keeps responsible data in compensation model for potential future purposes
* refactors registration_office and conservation_office to map onto KonovaCodes instead of own Organization model
* adds str_as_office property-method to KonovaCode to provide an easy way of rendering template data
* adds missing highlighting in case of missing information about registration office and conservation office
* adds payment-comment relation in NewPaymentForm
* drops transfer note form field (may not be used anyway) and replace it with comment
* adds/updates translations
* fixes created timestamp in detail views where modified needs to be displayed
* adds fallback timestamp if data has not been edited, yet --> show created timestamp
* fixes bug where deleting of certain data didn't redirect to the index view
* adds quality_check() method for EMA, needed for recording
* adds all functions which are provided for compensations to EMA
* adds/updates translations
