Add typed variants of UserData and user_data_impl macros

[Tired-Fox]

• Add support for typed user data derive and impl macros.
• Impl Macro improvements
  • Support for field getter and setters
  • Support for static fields with const impl fields
  • Support for static fields with impl functions

/// Custom action
#[derive(Clone, TypedUserData)]
enum Custom {
    A,
    B(
        /// Variant B Data
        String,
    ),
    C {
        name: String,
        /// Age of variant C
        age: u8,
    },
    D(
        /// Variant D Data
        u32,
    ),
}

#[typed_user_data_impl]
impl Custom {
    /// Static field
    const COUNT: usize = 10;

    /// Static field fetched once
    #[field(rename = "PI")]
    fn pi() -> f32 {
        3.14
    }

    /// Support for float infinity
    #[field(rename = "INF")]
    fn inf() -> f32 {
        f32::INFINITY
    }

    /// Support for float nan
    #[field(rename = "NAN")]
    fn nan() -> f32 {
        f32::NAN
    }

    /// Field getter `add_field_function_get`
    #[getter("direction")]
    fn get_direction(&self) -> String {
        "west".into()
    }

    /// Field getter `add_field_function_set`
    #[setter("direction")]
    fn set_direction(&self, input: String) {
        _ = input;
    }

    /// Get the message based on the variant
    #[method]
    fn message(&self) -> String {
        match self {
            Self::A => "Hello, world!".into(),
            Self::B(msg) => msg.clone(),
            Self::C { name, age } => format!("{name} age {age}"),
            Self::D(count) => count.to_string(),
        }
    }
}

[Tired-Fox]

Closes #21