Add Derive for Api

[ecton]

The Api trait should be deriveable:

struct MyType;

impl Api for MyType {
  type Response = OtherType;
  type Error = bonsaidb::core::api::Infallible;

  fn name() -> ApiName {
    ApiName::new("authority", "name")
  }
}

Should be able to be derived as:

#[derive(Api)]
#[api(authority = "authority", name = "name", response = OtherType, error = Infallible]
struct MyType;

Response is required. Error should be optional. If not specified, it should use bonsaidb_core::api::Infallible. Authority can be optional the same way the other derives work.

@ModProg

[ModProg]

bonsaidb_core::api::Infallible

probably should remember to change that to ! whenever that comes around 😆

[ecton]

probably should remember to change that to ! whenever that comes around

Only if Serde supports ! with Serialize/Deserialize, which I don't anticipate based on this closed issue. That's the primary reason for having a different type than std::convert::Infallible -- due to orphan rules I can't implement Serialize/Deserialize for std::convert::Infallible, and similarly, I wouldn't be able to for the never type either.

[ModProg]

That makes sense, but when ! is stabilized, it would probably make sense to ask serde to add an implementation for it again.