Change Ids representation from enums to unsigned integer wrapper

[UltraMachine]

Allows handling unknown ids in non-panicking way, while not breaking existing code, since associated constants can be referenced the same way as enum variants: SomeId::VariantX

Example code:

use std::fmt;

#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
#[repr(transparent)]
pub struct SomeId(u32);

#[allow(non_upper_case_globals)]
impl SomeId {
    pub const Variant1: Self = Self(1);
    pub const Variant2: Self = Self(2);
    pub const Variant3: Self = Self(3);

    pub fn other(id: u32) -> Self {
        Self(id)
    }
}

impl fmt::Display for SomeId {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match *self {
            Self::Variant1 => write!(f, "Variant1"),
            Self::Variant2 => write!(f, "Variant2"),
            Self::Variant3 => write!(f, "Variant3"),
            _ => write!(f, "Other({})", self.0),
        }
    }
}