Property that auto populates middleware on construction

[Ovyerus]

This would make it easier when extending the Erisa class, as users would need less "runtime" boilerplate and can make sure that everything is needed in this case.

Perhaps something like this

class MyBot extends Erisa {
    middleware = [commands(), logger()];
}

Question is, do we want to just pass the function, or the results from the function. Latter could look like:

class MyBot extends Erisa {
    middleware = [[commands, {options}], [logger, {options}]];
}

Would need to think about it.