Code Generator for Go Types

[chipshort]

This adds a code generator for the Go types we need in wasmvm. It uses cosmwasm-schema to generate json schema from a type and traverses that to generate Go code from it.
I'm open to refactoring recommendations. Some of it is a bit messy (though that's mostly because of the schemars api and the many cases that have to be covered)

[webmaster128]

Very very nice!

We need naming convension conversion for acronyms. E.g. pub struct Ibc3ChannelOpenResponse vs. type IBC3ChannelOpenResponse struct or field names pub port_id: String vs. PortID string. Maybe a map which converts words to uppercase (Ibc, Id, ..)

[webmaster128]

This should be string by default and only Checksum in cases where we have a 32 byte checksum.

Do we have a way to annotate this somehow in Rust?

[chipshort]

That's a bit of a problem. What we could do is use #[schemars(title = "Checksum")] on the field. That would set metadata.title for the field in the schema.

[webmaster128]

Oh but what we also do is change CodeInfoResponse::checksum from HexBinary to cosmwasm_std::Checksum. With that we can map

// both hex strings in JSON
"HexBinary" => Some("string"),
"Checksum" => Some("Checksum"),

[chipshort]

Unfortunately, that only works if we make Checksum a newtype like struct Checksum(HexBinary), which would be a contract-breaking change for CodeInfoResponse.
Type aliases are already resolved to their underlying types at the json schema level (type Checksum = HexBinary becomes HexBinary in the schema).

[webmaster128]

Yeah, I'm thinking about a source breaking change here. In contrast to HexBinary, Checksum would guarantee to store 32 bytes. We have Checksum already and would just have to add serde.

[chipshort]

Oh, I see now, we have Checksum in cosmwasm-vm. Yeah, that seems like a good solution and would even make the type a bit nicer (as you mentioned, guaranteed 32 bytes, but also the docs specify that it is sha256, etc.).
But that means this would have to wait for 2.0, right?

[webmaster128]

we have Checksum in cosmwasm-vm.

Ah, right. I did not realize we don't have it in cosmwasm-std yet. But yes, this can be the same type by moving it to cosmwasm-std and adding serde support.

wait for 2.0, right?

Yes. In the meantime we can keep "HexBinary" => Some("Checksum"), because this is only used in one place.

[chipshort]

Alright, I created an issue for that: #1835
Anything left to do here, or can we merge?

[webmaster128]

🔥🔥🔥 Now we're talking

[webmaster128]

Very nice! Let's merge here and see if that is useful for #1788