LOG: Encryptable log write access / previous values

[lkleisa]

The idea of this feature is to log all encryptables read or edit accesses, to make it more transparent what users are accessing or editing encrypted data. More you should see, who changed which attribute with which value.

This feature is based on: Access- and changelog conception and the previous feature #564

Always run the E2E-tests if you change something in the frontend, run the backend-tests if you change something in the backend and test always manually

ToDo

• Familiarize your-self with paper-trail gem
• Check if editing for example description only does not re-encrypt given username, password. If so, make sure re-encrypt is only done if value has changed. we have to track if there were changes in username or password to show it
• Do not show what changed exactly for attribute description, just display that the value was changed but no previous value. (description can be a pretty long text and would kill the layout/table)
• Enable paper trail to also log update events https://github.com/paper-trail-gem/paper_trail#2a-choosing-lifecycle-events-to-monitor
• Add new controller Api::Encryptables::VersionsController
  • add new route /api/encryptables/:encryptable_id/versions/:id
  • get version entry and initialize a Encryptable object with params from object column in versions table
  • decrypt encryptable to get cleartext values of password, username
  • use encryptables serializer https://github.com/puzzle/cryptopus/blob/master/app/serializers/encryptable_serializer.rb
  • this endpoint is used for fetching previous values of username, password
  • only allow access to this endpoint if encryptable is accessible (see EncryptablePolicy)
• Add adapter and model in EmberJS UI
• Fetch cleartext value in UI if user wants to retrieve previous values (show previous password/username)
  • if it's not possible to only retrieve for example username, just display both, username and password
• extend table component
• add frontend and system (e2e) tests/specs