Use custom derive ser/de instead of std::io

[Dentosal]

Closes #443. Initial work migrated from FuelLabs/fuel-tx#190, and the improved and adapted to the current system.

This PR replaces hand-written type serialization code with a macro-derived ones. It removes a lot of error-prone boilerplate code and makes it easier to add new types. The old implementation using io::{Read, Write} was not no_std compatible, but the new generated code is. The new implmentation also allows computing many sizes at compile time.

The new serialization framework is called canonical. It's used similarly to serde:

use fuel_types::canonical::{Serialize, Deserialize};

#[derive(Serialize, Deserialize)]
pub struct ExampleStruct {
    inner: InnerStruct,
    dynamically_sized: Vec<u8>,
    primitive: u64,
    #[canonical(ignore)]
    primitive: u64,
}

Several datatype-level attributes are also accepted:, expecially for enums.

structs

fuel-vm/fuel-derive/src/attribute.rs

Lines 59 to 61 in 4af7c63

	/// The struct is prefixed with the given word.
	/// Useful with`#[canonical(inner_discriminant)]`.
	pub prefix: Option<TokenStream>,

enums

fuel-vm/fuel-derive/src/attribute.rs

Lines 81 to 95 in 4af7c63

	/// Use a custom type as a discriminant. Mapped using `TryFromPrimitive` and `Into`.
	pub discriminant: Option<TokenStream>,
	/// Same as `discriminant`, but each field is prefixed with the discriminant,
	/// so it's not removed when the enum itself is deserialized.
	pub inner_discriminant: Option<TokenStream>,
	/// Replaces calculation of the serialized static size with a custom function.
	pub serialized_size_static_with: Option<TokenStream>,
	/// Replaces calculation of the serialized dynamic size with a custom function.
	pub serialized_size_dynamic_with: Option<TokenStream>,
	/// Replaces serialization with a custom function.
	pub serialize_with: Option<TokenStream>,
	/// Replaces deserialization with a custom function.
	pub deserialize_with: Option<TokenStream>,
	/// Determines whether the enum has a dynamic size when `serialize_with` is used.
	pub SIZE_NO_DYNAMIC: Option<TokenStream>,

[bvrooman]

Can we now remove the mem_layout macro and related code in this PR?

[bvrooman]

I've reviewed 66 files at this point - I will continue with the last stretch tomorrow.

[Voxelot]

What happens when an enum uses #[canonical(inner_discriminant = Type)], but the corresponding structs of each variant don't use #[canonical(prefix = Type::P1)]? If we always need to specify the prefix along with discriminant, should we have some kind of check at compile time to ensure it's setup correctly?

edit: disregard - after looking at the serialization helpers for inputs, it seems like there's not an easy way to verify this at compile time atm since the prefix may be set by custom logic.

[Voxelot]

Good call on removing discriminant, it was a little confusing how it was suppose to be used compared to inner_descriminant.

[Voxelot]

Wrote some local fuzz tests to check the ability of roundtrip serialization between this and the original encoding, and didn't find any issues. I think we're probably good to ship this.