Consider long-term refactorings from #617

[endgame]

In #617 , @brendanhay said:

Changes that I wanted in amazonka >= 2.0, but probably aren't going to happen:

1. ~~Migrate entirely from Network.AWS.* style namespaces to Amazonka.*.~~ Done

2. ~~Supersede (via deprecation) Network.AWS and Control.Monad.Trans.AWS in favour of something similar and completely effect agnostic of the form send :: Env -> .... You can then use whatever effects system floats your boat and I don't have to maintain mtl nonsense.~~ Done

3. Removal of http-conduit, xml-conduit, and resourcet in favour of a sendWith :: ... -> (a -> IO b) -> b continuation style.

4. Replace Network.AWS.{Text,ByteString,Log} with http-api-data.

5. Removal of non-essential dependencies (despite 3.)

This is a reminder to go over that list once 2.0 is final, and decide whether we want to do any of these for real.