Integrate beam with the moto package

[tathougies]

beam-migrate is a mess, and the non-working CLI tool drags the codebase down.

Moto seems to be a sensible migrations tool that can be used to migrate all sorts of things. It would be nice to have a beam integration so that this set-up works out of the box.

[theobat]

Just adding the hackage link for the layperson