Elektra: Use Case: Key validation

Elektra 0.8.24

Use Case: Key validation

## Summary

- Title: Key validation
- Scope: Configuration
- Level: User Goal
- Actors: User (usually a sysadmin)
- Brief: User gets feedback about a key's contents.

## Scenarios

- Extends: Modifying keys, Adding keys, Drag & Drop keys.
- Main success scenario: If the entered data passes the validation, it is sent to the backend and saved to the key database.
- Alternative scenario: User enters data that fails the field validation, the input field is marked as invalid (e.g. with a red color and some information text) and the data is NOT sent to the backend.
- Alternative scenario: User enters data that violates a validation rule, an error message is shown and the data is NOT saved to the key database.
- Error scenario: Technical problems while persisting to the key database. The user is informed about the problem.
- Postcondition: The updated key is persisted to the database.
- Non-functional Constraints: -