Add Dex pallet (#407)

* Move pallet-asset-conversion

* update licensing

* initial integration

* Integrate Currency & Assets types

* integrate liquidity tokens

* fmt

* integrate dex pallet tests

* fmt

* compilation error fixes

* integrate dex benchmarks

* fmt

* cargo clippy

* replace all occurrences of "asset" with "coin"

* add the actual add liq/swap logic to in-instructions

* add client side & tests

* fix deny

* Lint and changes

- Renames InInstruction::AddLiquidity to InInstruction::SwapAndAddLiquidity
- Makes create_pool an internal function
- Makes dex-pallet exclusively create pools against a native coin
- Removes various fees
- Adds new crates to GH workflow

* Fix rebase artifacts

* Correct other rebase artifact

* Correct CI specification for liquidity-tokens

* Correct primitives' test to the standardized pallet account scheme

---------

Co-authored-by: Luke Parker <lukeparker5132@gmail.com>

substrate/primitives/src/networks.rs

@@ -42,6 +42,8 @@ pub const COINS: [Coin; 5] = [Coin::Serai, Coin::Bitcoin, Coin::Ether, Coin::Dai
   Copy,
   PartialEq,
   Eq,
+  PartialOrd,
+  Ord,
   Hash,
   Debug,
   Serialize,
@@ -61,6 +63,10 @@ pub enum Coin {
 }
 
 impl Coin {
+  pub fn native() -> Coin {
+    Coin::Serai
+  }
+
   pub fn network(&self) -> NetworkId {
     match self {
       Coin::Serai => NetworkId::Serai,
@@ -101,6 +107,10 @@ impl Coin {
       Coin::Monero => 12,
     }
   }
+
+  pub fn is_native(&self) -> bool {
+    matches!(self, Coin::Serai)
+  }
 }
 
 // Max of 8 coins per network