Implement measures checks

[OkonSamuel]

We need to Implement measures checks for measures passed to out_of_bag_measure parameter of EnsembleModel.
Currently any Vector of Julia objects can be passed as input to the out_of_bag_measure parameter of EnsembleModel, whereas this should only allow passing a vector of MLJ measures.
Also, the current implementation allows observation weights to be passed to any measure, even those measures supporting only class-weights. Hence checks should be implemented to avoid this and throw an informative error message.
Finally, users can even pass measures that are only valid for classifiers to DeterministicEnsembleModels making deterministic predictions. Check have to be implemented to avoid this also.

These checks could be similar to the one found here

[ablaom]

Closing in favour of #26.