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/client/tests/common/dex.rs

@@ -0,0 +1,55 @@
+use serai_runtime::primitives::{Coin, Amount};
+
+use serai_client::{Serai, SeraiDex, PairSigner};
+use sp_core::{sr25519::Pair, Pair as PairTrait};
+
+use subxt::config::extrinsic_params::BaseExtrinsicParamsBuilder;
+
+use crate::common::tx::publish_tx;
+
+#[allow(dead_code)]
+pub async fn add_liquidity(
+  serai: &Serai,
+  coin: Coin,
+  coin_amount: Amount,
+  sri_amount: Amount,
+  nonce: u32,
+  pair: Pair,
+) -> [u8; 32] {
+  let address = pair.public();
+
+  let tx = serai
+    .sign(
+      &PairSigner::new(pair),
+      &SeraiDex::add_liquidity(coin, coin_amount, sri_amount, Amount(1), Amount(1), address.into()),
+      nonce,
+      BaseExtrinsicParamsBuilder::new(),
+    )
+    .unwrap();
+
+  publish_tx(serai, &tx).await
+}
+
+#[allow(dead_code)]
+pub async fn swap(
+  serai: &Serai,
+  from_coin: Coin,
+  to_coin: Coin,
+  amount_in: Amount,
+  amount_out_min: Amount,
+  nonce: u32,
+  pair: Pair,
+) -> [u8; 32] {
+  let address = pair.public();
+
+  let tx = serai
+    .sign(
+      &PairSigner::new(pair),
+      &SeraiDex::swap(from_coin, to_coin, amount_in, amount_out_min, address.into()),
+      nonce,
+      BaseExtrinsicParamsBuilder::new(),
+    )
+    .unwrap();
+
+  publish_tx(serai, &tx).await
+}