Nicer interface for browsing captured problems

Sometimes the problem/solution is not explicitly available in user's code. Thanks to low-level data capturing we still have access to these (in `dwave.inspector.storage`), but the interface is quite awkward. For example to visualize one QMI:
```
dwave.inspector.storage.index_resolved_problems()
problem_id = list(dwave.inspector.storage.problemdata.keys())[0]
dwave.inspector.show(problem_id)
```

Few fixes possible:
- order all problems in time
- write interface for browsing problems, without the need for explicit indexing
- extend `show` to accept `problem_index: int` (or maybe even strings like `"last"` and `"first"`?)

Note this can handle only QMIs for now. For fully automated logical problem inspection, we need to extend data capture to samplesets.