| Elektra 0.11.0

Use Case: `Key` Ordering

# Summary

- Scope: `libelektra-core`
- Level: Developer Goal
- Actors: Core, Caller
- Brief: Order comparison between `Key`s

# Scenarios

- Precondition:
  - `Key` K1 has been created
  - `Key` K2 has been created
- Main success scenario:
  - Caller reads names N1 and N2 of `Key` K1 and `Key` K2
  - Caller requests order comparison between N1 and N2
  - Core returns
    - N1 is sorted before N2
    - N1 and N2 are sorted to the same place
    - N1 is sorted after N2
- Alternative scenario: -
- Error scenario: -
- Postcondition: -
- Non-functional Constraints:
  - The order comparison with MUST form a total order over `Key`s.
  - Each of the possible results MAY be a single value, but it MAY also be a whole class of value (e.g. negative integer).