This commit splits the current `ComponentValue` trait into three
separate traits:
* `ComponentType` - contains size/align/typecheck information in
addition to the "lower" representation.
* `Lift` - only contains `lift` and `load`
* `Lower` - only contains `lower` and `store`
When describing the original implementation of host functions to Nick he
immediately pointed out this superior solution to the traits involved
with Wasmtime's support for typed parameters/returns in exported and
imported functions. Instead of having dynamic errors at runtime for
things like "you can't lift a `String`" that's instead a static
compile-time error now.
While I was doing this split I also refactored the `ComponentParams`
trait a bit to have `ComponentType` as a supertrait instead of a subtype
which made its implementations a bit more compact. Additionally its impl
blocks were folded into the existing tuple impl blocks.
11ff9650e5