Remove unnecessary MonadIO and MonadFail uses

[glguy]

MonadIO usage in this library was causing unnecessary liftIO calls to be littered across the package. The package doesn't need any of this generality, and anyone wanting to use MonadIO outside of the package can use liftIO as needed. It might make sense to rely on MonadIO if there were other type classes in use as well, but without that the generalization is premature and make this more complex than needed to perform the task. This also cleans up some of the MonadFail needs that were coming up because of some uses of fail leaking outside of the other liftIO wrappers.

[jtdaugherty]

Thank you!

[jtdaugherty]

anyone wanting to use MonadIO outside of the package can use liftIO as needed

FWIW, I don't think this addresses my comment elsewhere; they can use liftIO to embed calls to e.g. Output fields in their own code, but if they were wanting for some reason to embed their own monadic values in the Output fields, liftIO doesn't help with that. Granted, given that the m isn't part of the Output type, I don't see what possible value anyone could gain by embedding their own m values in the Output fields, so I doubt it's going to cause a lot of trouble.