WEB3-240: Re-export alloy from risc0-ethereum-contracts and risc0-steel

[nategraf]

One the common pieces of feedback we do from the Boundless private devnet was that alloy versioning was one of the biggest challenges. In particular, a developer would encounter a type mismatch error where "alloy::Foo is the not the same as alloy::Foo", which is a somewhat difficult to debug issue related to having two version of alloy in your crates tree. Because alloy is pre-1.0 and changing often, there is no silver bullet here.

One rule of thumb though is that an types that appear in the public interface of a crate should be (re-)exported from that crate. In our case, we do have alloy types in our public interface. So, if we apply this rule, we should export the types we use from alloy, and the easiest way to do so is to re-export the alloy crate. This helps with the versioning challenges because if the project ends up needing two distinct versions of alloy (e.g. one dependency specifies 0.4 and another 0.6) then the developer can use the re-exported alloy as an anchor for any places they are using risc0-steel or risc0-ethereum-contracts.