smithy4s-cats: provide transformers for EitherT

[kubukoz]

Now that we have a Cats module, we should provide a generic (abstracting away IO) version of:

new Transformation.AbsorbError[EitherT[IO, *, *], IO] {
      def apply[E, A](fa: EitherT[IO, E, A], injectError: E => Throwable): IO[A] =
        fa.leftMap(injectError).rethrowT
    }

and the corresponding Transformation.SurfaceError transformation.

[Baccata]

I don't have a problem with that

[kubukoz]

we could also have some derivation of Transformation / conversions of ~> so that smithy4s.~> can be used interchangeably with cats.~>.