[feature] #3941, #3612: Remove expressions

[Arjentix]

Description

The main idea was to move all expressions into executor. After a discussion with @mversic we decided not to implement any of them inside default_executor, but to have an example executor to show PoC.

• All expressions were removed
• #[model] together with ffi have become useless for data_model because in future clients should link against executor_data_model. So I partly removed them. This might need future investigation

I wii squash all my commits before merge.

Linked issue

• Closes Move all expression evaluation from host into Executor #3941
• Closes [suggestion] Make illegal instructions unrepresentable #3612

Benefits

• Much less code
• No stillborn expression system inside data_model and core
• Types for ISI now can't contain unsupported parameters

Follow up tasks

• Reconsider ffi for data_model
• Make block content opaque
• Write example executor with expressions or even DSL

Checklist

• I've read CONTRIBUTING.md
• I've used the standard signed-off commit format (or will squash just before merging)
• All applicable CI checks pass (or I promised to make them pass later)
• (optional) I've written unit tests for the code changes
• I replied to all comments after code review, marking all implemented changes with thumbs up

[mversic]

this is how I would prefer doing it:

Suggested change

	/// Constructs a new [`BurnBox`] to burn [`Asset`] of [`Quantity`] type.
	pub fn asset_quantity(quantity: u32, asset_id: <Asset as Identifiable>::Id) -> Self {
	Self::Asset(AssetBurnBox::Quantity(Burn::new(quantity, asset_id)))
	}
	/// Constructs a new [`BurnBox`] to burn [`Asset`] of [`BigQuantity`] type.
	pub fn asset_big_quantity(quantity: u128, asset_id: <Asset as Identifiable>::Id) -> Self {
	Self::Asset(AssetBurnBox::BigQuantity(Burn::new(quantity, asset_id)))
	}
	/// Constructs a new [`BurnBox`] to burn [`Asset`] of [`Fixed`] type.
	pub fn asset_fixed(quantity: Fixed, asset_id: <Asset as Identifiable>::Id) -> Self {
	Self::Asset(AssetBurnBox::Fixed(Burn::new(quantity, asset_id)))
	}
	/// Constructs a new [`BurnBox`] to burn [`Asset`]
	pub fn asset(quantity: impl Into<AssetValue>, asset_id: AssetId) -> Self {
	match quantity.into() {
	AssetType::Quantity(quantity) => Self::Asset(AssetBurnBox::Quantity(Burn::new(quantity, asset_id))),
	AssetType::BigQuantity(quantity) => Self::Asset(AssetBurnBox::Quantity(Burn::new(quantity, asset_id))),
	AssetType::Fixed(quantity) => Self::Asset(AssetBurnBox::Quantity(Burn::new(quantity, asset_id))),
	}
	}

I think this makes a better API but I see we might not be able to do it because of AssetValue::Store

[Erigara]

LGTM