Add Circuit1

[martijnbastiaan]

The current implementation of Circuit is doing quite a lot of bundling and unbundling. For example, see:

clash-protocols/src/Protocols/Df/Simple.hs

Lines 238 to 239 in 1e5be51

	route =
	Circuit (B.second C.unbundle . C.unbundle . fmap go . C.bundle . B.second C.bundle)

This needs to happen in every component due to the definition of Fwd/Bwd. We, unfortunately, need to do that as Fwd/Bwd could result in Signals on any domain. If we would instead define:

newtype Circuit1 dom a b =
  Circuit1 ( (Fwd1 dom a, Bwd1 dom b) -> (Bwd1 dom a, Fwd1 dom b) )

class Protocol1 (dom :: Domain) a where
  type Fwd1 (dom :: Domain) (a :: Type) = (r :: Type) | r -> dom a
  type Bwd1 (dom :: Domain) (a :: Type) = (r :: Type) | r -> dom a

  fromCircuit1 ::
    Protocol1 dom b =>
    Circuit1 dom a b ->
    Circuit a b

  toCircuit1 ::
    Protocol1 dom b =>
    Circuit a b ->
    Circuit1 dom a b

..we wouldn't have to go through all the unbundling.

I expect almost all implementations could live under Circuit1 with their Circuitcounterparts simply doing fromCircuit1 foo. We should measure before we commit ot this of course.

Edit: This would need changing the plugin too.