Murko: double meaning of MurkoResult

We use `MurkoResult` dataclass to contain results as they come from Murko as well as result objects as used in the MurkoResultsDevice`. These are in different formats so we should not use the same dataclass for both, even though at runtime it works.

We could also use pydantic to increase validation around serialised data.

## Acceptance Criteria
- Specific criteria that will be used to judge if the issue is fixed