* adds related object overview in detail view
* adds comment field to payment model for 'Verwendungszweck'
* simplifies intervention urls
* adds translations
* 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
