Switch away from cipher-aes128
cipher-aes128 is not quite as well-maintained as cryptonite / crypton. Also we get almost all the functionality we need from crypton / cryptonite so we don't need to take dependencies on both of these crypto libraries. As it turns out, if we use cryptonite for aes128 then we can also drop our dependencies on:
- cereal
- crypto-api
- tagged
This change also removes the monad-loops dependency too because I noticed we weren't using it.