* 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
* refactors base attributes created and deleted into UserActionLogEntry foreign keys
* refactors all related queries and process logic
* fixes binding_on into binding_date in intervention/detail/view.html
* adds basic __str__ for some models
*
* splits Intervention model into main components
* Compensation (main object)
* ResponsibilityData (holds organizations and handler) - same as used for intervention
* This way data can be extended more easily in the future
* refactors deadlines
* adds (WIP) detail view for interventions
* renames typo in conservations_file_number to conservation_file_number
* adds simple has_access check for intervention objects for given users
* renames occurences of "Registered" to "Recorded" (verzeichnen)
* adds an informing message for detail view of intervention objects which are not editable for a user
* adds GeometryAdmin
* adds fallback DEFAULT_SRID for Geometry model
* adds translations
