chore: create macros to generate impl From<T> on wrapper structs and enums

[ashneverdawn]

We often use this pattern to be able to use the wasmbingen macro and implement traits on foreign types from Warp:

#[wasm_bindgen]
pub struct WrapperType(ForeignType);

impl From<WrapperType> for ForeignType {
    fn from(value: WrapperType) -> Self {
        value.0
    }
}

impl From< ForeignType > for WrapperType {
    fn from(value: ForeignType) -> Self {
        Self(value)
    }
}

Another frequent similar case is where we wrap a foreign enum for the same reasons:

#[wasm_bindgen]
pub enum WrapperEnum {
    Variant1,
    Variant2,
    Variant3,
}

impl From<ForeignEnum> for WrapperEnum {
    fn from(value: ForeignEnum) -> Self {
        match value {
            ForeignEnum::Variant1 => WrapperEnum::Variant1,
            ForeignEnum::Variant2 => WrapperEnum::Variant2,
            ForeignEnum::Variant3 => WrapperEnum::Variant3,
        }
    }
}

impl From<WrapperEnum> for ForeignEnum {
    fn from(value: WrapperEnum) -> Self {
        match value {
            WrapperEnum::Variant1 => ForeignEnum::Variant1,
            WrapperEnum::Variant2 => ForeignEnum::Variant2,
            WrapperEnum::Variant3 => ForeignEnum::Variant3,
        }
    }
}

We want to create a couple macros that will handle automatic code generation of these repetitive impl blocks. The macros would generate the same code as above, and might be used like so:

#[wasm_bindgen]
#[foreign_type_wrapper]
pub struct WrapperType(ForeignType);

#[wasm_bindgen]
#[foreign_enum_wrapper(ForeignEnum)]
pub enum WrapperEnum {
    // the variants should be generated by the macro too
}

by the way, a macro must be defined in its own crate with this in Cargo.toml:

[lib]
proc-macro = true

See: https://doc.rust-lang.org/book/ch19-06-macros.html