[FEAT] - Validate numeric values in the settings dictionary

[ThomasHepworth]

I think it makes sense to warn the user if their initial settings values look unreasonable.

For example, if a user were to input 0.5 for probability_two_random_records_match, then we'd probably want to warn them that this value looks too high and they are likely to end up with unrealistic results (and enormous clusters...).

I'd imagine that part of this could be resolved directly within the schema, were we to add upper and lower bounds.

See the json schema documentation for more info on arguments we can use.