* adds model and form mixin for PIK
* integrates mixins for compensation, ema and ecoaccount
* adds migration files
* extends API
* extends API test data
* adds is_xy fields to compensation, ema and ecoaccount reports
* adds is_pik information to detail views
* adds/updates translations
* adds creation tests with minimum data for intervention, compensation, ema and ecoaccount
* fixes bug where empty geometry would not be created properly using the API
* reworks key fetching from POST data, so inproperly stated keys will lead to an error for the API user, instead of silently working and use default data
* adds some logical checks for deductable_surface of eco account creation using api
* fixes bug that would have occured on creating compensations via api
* adds support for PUT and POST of Ema
* moves set_responsibility() and set_legal() from Intervention API Serializer into proper Mixins where they belong to
