* 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
*
* adds UserActionLogEntry model to user/models.py
* wraps user and timestamp info
* can be extended for more information in the future
* refactors all filtering and accessing on values
* 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
* adds user access relation to certain models
* adds pagination to tables
* adds checked_on/_by attributes to intervention model
* adds custom column rendering for checked and registered columns
* adds first simple index filtering of default interventions for user
* adds translations
