* 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 more log details on adding/removing documents
* fixes bug in admin backend where restoring of non-compensation entries led to an error
* fixes bug where deleting of revocation without an attached file would lead to an error
* adds support for payment adding/deleting to intervention log
* adds support for deduction adding/deleting to intervention/ecoaccount log
* improves code snippets
* drops add_deduction() methods for ecoaccount and intervention in favor of simpler creation in NewDeductionModalForm
* adds messages
* adds/updates translations
* removes admin backend views which are not important for production
* adds filtering functionalities on index views
* simplifies detail views on intervention, compensation, ecoaccount and ema
* adds autocomplete fields on detail views
* adds handy horizontal filter fields on detail views
