Properly treat cross-stage type variables in typed quotes

The crux of the problem is that we didn't consider cross-stage persistence for type variables. With the advent of type applications this has become more pertinent but has been a problem for a long time in untyped splices.

The original program presented in the ticket was

foo :: forall a . Q (TExp Int)
foo = [|| get @a ||]

This should be rejected immediately as a is bound at stage 0 and used at stage 1 which is a stage violation.

However, we can fix this by implicitly lifting type variables like we do for term variables.

To do this, we define a new built-in class called LiftT with a single method which lifts a type to its representation.

class LiftT (t :: k) where
   liftTyCl :: Q Type

Instances for this class are solved automatically by the compiler for all types.

Now if we use a cross-stage variable, like for terms, we have to add a class constraint which says we can represent it.

foo :: forall a . LiftT a => Q (TExp Int)
foo = [|| get @a ||]

This is then implicitly desugared into

foo :: forall a . Typeable a => Q (TExp Int)
foo = [|| get @$$(liftTyCl @a) ||]

where liftTyCl turns a type into a Q Type.

The knowledgeable reader will know that this problem has already been solved in the same manner for Cloud Haskell but obviously the code paths are completely different.