Elektra: Use Case: Delete configuration snippet

Elektra 0.8.24

Use Case: Delete configuration snippet

## Summary

- Title: Delete configuration snippet
- Scope: Entry Management
- Level: User Goal
- Actors: Authenticated user (snippet owner), Moderator
- Brief: Users can delete their own database entries. Moderators can also delete configuration snippets of other users.

## Scenarios

- Precondition: Authenticated, sufficient permissions, snippet details page opened
- Main success scenario: Configuration snippet has been deleted successfully. A success response is returned and the user, if necessary, redirected to the entry overview.
- Alternative scenario: The specified snippet cannot be found (wrong URI) or the user has insufficient permissions to delete it. Either way the user is informed about the error by a response and redirected to the overview if necessary.
- Error scenario: Technical problems prevent the deletion process from completing. The user is informed about the issue.
- Postcondition: Configuration snippet has been deleted from the database and can neither be found through search, nor be viewed in detail anymore.
- Non-functional Constraints:
  - Moderative feature
  - Essential functionality of the service