Adjust `model_fetch_run()` to optionally fetch input data

[dfsnow]

Currently, in order to run reports you need both the input/ and output/ data to be aligned (matching the metadata of your target run). This can be cumbersome when testing as often the input/ data will have changed since your target run. We should add an option argument to model_fetch_run() that grabs the appropriate data from the DVC cache.