Use open kinds for better error messages

Currently we use kind `*` as our generic open kind, which means nonsensical type-level expressions (like applying a block to a crypto argument rather than an era, say) will not result in helpful error message. Unfortunately Haskell does not allow us to declare new open kinds, but we can encode them:

```haskell
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE KindSignatures #-}

module T where

import Data.Kind

data ConsensusProtocolKind

type ConsensusProtocolOpenKind = ConsensusProtocolKind -> Type

data PBFt (n :: ConsensusProtocolKind)

class ConsensusProtocol (p :: ConsensusProtocolOpenKind) where

instance ConsensusProtocol PBFt where

data Block (p :: ConsensusProtocolOpenKind)

foo :: Block Int -> ()
foo = undefined
```

leading to

```
T.hs:20:14: error:
• Expected kind ‘ConsensusProtocolOpenKind’, but ‘Int’ has kind ‘*’
• In the first argument of ‘Block’, namely ‘Int’
```

This requires adding a dummy argument to `PBFt` (and other things), but since that argument is never ever instantiated, it only appears at the def site, not at use sites.