Redo primitives, abi

Consolidates all primitives into a single crate. We didn't benefit from its
fragmentation. I'm hesitant to say the new internal-organization is better (it
may be just as clunky), but it's at least in a single crate (not spread out
over micro-crates).

The ABI is the most distinct. We now entirely own it. Block header hashes don't
directly commit to any BABE data (avoiding potentially ~4 KB headers upon
session changes), and are hashed as borsh (a more widely used codec than
SCALE). There are still Substrate variants, using SCALE and with the BABE data,
but they're prunable from a protocol design perspective.

Defines a transaction as a Vec of Calls, allowing atomic operations.

substrate/abi/src/coins.rs

@@ -1,25 +1,70 @@
-use serai_primitives::{Balance, SeraiAddress};
+use borsh::{BorshSerialize, BorshDeserialize};
 
-pub use serai_coins_primitives as primitives;
-use primitives::OutInstructionWithBalance;
+use serai_primitives::{
+  address::SeraiAddress, balance::Balance, instructions::OutInstructionWithBalance,
+};
 
-#[derive(Clone, PartialEq, Eq, Debug, scale::Encode, scale::Decode, scale_info::TypeInfo)]
-#[cfg_attr(feature = "borsh", derive(borsh::BorshSerialize, borsh::BorshDeserialize))]
-#[cfg_attr(feature = "serde", derive(serde::Serialize))]
-#[cfg_attr(all(feature = "std", feature = "serde"), derive(serde::Deserialize))]
+/// A call to coins.
+#[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
 pub enum Call {
-  transfer { to: SeraiAddress, balance: Balance },
-  burn { balance: Balance },
-  burn_with_instruction { instruction: OutInstructionWithBalance },
+  /// Transfer these coins to the specified address.
+  transfer {
+    /// The address to transfer to.
+    to: SeraiAddress,
+    /// The coins to transfer.
+    coins: Balance,
+  },
+  /// Burn these coins.
+  burn {
+    /// The coins to burn.
+    coins: Balance,
+  },
+  /// Burn these coins with an `OutInstruction` specified.
+  burn_with_instruction {
+    /// The `OutInstruction`, with the coins to burn.
+    instruction: OutInstructionWithBalance,
+  },
 }
 
-#[derive(Clone, PartialEq, Eq, Debug, scale::Encode, scale::Decode, scale_info::TypeInfo)]
-#[cfg_attr(feature = "borsh", derive(borsh::BorshSerialize, borsh::BorshDeserialize))]
-#[cfg_attr(feature = "serde", derive(serde::Serialize))]
-#[cfg_attr(all(feature = "std", feature = "serde"), derive(serde::Deserialize))]
-pub enum Event {
-  Mint { to: SeraiAddress, balance: Balance },
-  Burn { from: SeraiAddress, balance: Balance },
-  BurnWithInstruction { from: SeraiAddress, instruction: OutInstructionWithBalance },
-  Transfer { from: SeraiAddress, to: SeraiAddress, balance: Balance },
+impl Call {
+  pub(crate) fn is_signed(&self) -> bool {
+    match self {
+      Call::transfer { .. } | Call::burn { .. } | Call::burn_with_instruction { .. } => true,
+    }
+  }
+}
+
+/// An event from the system.
+#[derive(Clone, PartialEq, Eq, Debug, BorshSerialize, BorshDeserialize)]
+pub enum Event {
+  /// The specified coins were minted.
+  Mint {
+    /// The address minted to.
+    to: SeraiAddress,
+    /// The coins minted.
+    coins: Balance,
+  },
+  /// The specified coins were burnt.
+  Burn {
+    /// The address burnt from.
+    from: SeraiAddress,
+    /// The coins burnt.
+    coins: Balance,
+  },
+  /// The specified coins were burnt with an `OutInstruction` specified.
+  BurnWithInstruction {
+    /// The address burnt from.
+    from: SeraiAddress,
+    /// The `OutInstruction` specified, and the coins burnt.
+    instruction: OutInstructionWithBalance,
+  },
+  /// The specified coins were transferred.
+  Transfer {
+    /// The address transferred from.
+    from: SeraiAddress,
+    /// The address transferred to.
+    to: SeraiAddress,
+    /// The coins transferred.
+    coins: Balance,
+  },
 }