* adds error message on intervention view if a payment has been added but no document has been uploaded yet
* adds same check to quality checker, meaning no intervention can be recorded which has a payment but no document
* adds trigger for sending data to egon on uploading a document in case of an already existing payment
* adds translations
* renames model ResponsibilityData into Responsibility
* renames model LegalData into Legal
* moves form->object saving logic into model
* refactors NewDocumentForm into special types for intervention, compensation, eco account and ema
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* adds AbstractQualityChecker as base for all quality checker instances
* adds InterventionQualityChecker, inheriting from AbstractQualityChecker
* adds functionality to InterventionQualityChecker
* adds/updates translations