Create `kzg-types` crate

[realbigsean]

Our consensus/types crate depends on our crypto/kzg crate, which imports c-kzg. The c-kzg dependency is annoying for using our types crate outside of lighthouse. I was thinking we could create a smaller crypto/kzg-types crate where we house anything in crypto/kzg we require in the consensus/types crate. And just import this kzg-types crate into kzg.

Things to do:

• stop using constants from c-kzg in our types
• instead we could add a compile time assertion in kzg that the constants set in kzg-types are equivalent to those set in c-kzg
• move the method BlobSidecar::random_valid off of the type and into the kzg crate so we don't require it in the types crate

[dknopik]

This kind of ties in with my idea to introduce features/optional dependencies in the types crate. Maybe we do not need a separate crate but can just introduce a feature called kzg to make the dependency optional?