* adds access checks depending on the current group confgiguration of a user
* removes buttons for adding/editing or removing data if default group is not set for a user
* removes buttons for adding/removing related data in unshared interventions
* removes shared-user setting from share menu of an intervention if user is not zb or ets
* renames has_access() from intervention Model into is_shared_with() for more clarity
* fixes bug in group check in_group() from utils.py
* compensations won't be listed in index table if related intervention has been deleted
* adds functionality for intervention remove button
* adds outcommented code
* adds configurable redirect_url for RemoveModalForm's process_request method
* adds translation
* 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 related eco account withdraw detail view to intervention detail view
* adds new route for removing withdraws using RemoveModalForm
* adds EcoAccountWithdraw model
* adds admin interfaces for EcoAccount and EcoAccountWithdraw
* adds message_templates.py to konova/utils for reusable messages
* splits related-documents.html and related-objects.html into separate templates for each related object type: compensations.html, documents.html, eco-account-withdraws.html and payments.html
* adds translations
* adds help texts to add payment form
* adds removing button for payments
* refactors user fetching into BaseForm
* adds generic RemoveModalForm which is intended to be used for every modal form which shall remove something
* adds translations
* removes unused html
* prepares payment amount field to be able to process german inputs like '1.000,50' which is not the international default
* adds modal form for adding payments
* generalizes generic_table_form.html for table-form-like usage in modal_form.html
* adds css enhancements for focused input fields
* adds BaseModalForm as specification to BaseForm, which inherits the BSModalForm class as well
* adds translations
