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/coins/primitives/src/lib.rs

@@ -12,7 +12,7 @@ use scale_info::TypeInfo;
 
 use serai_primitives::{Balance, SeraiAddress, ExternalAddress, Data, system_address};
 
-pub const FEE_ACCOUNT: SeraiAddress = system_address(b"FeeAccount");
+pub const FEE_ACCOUNT: SeraiAddress = system_address(b"Coins-fees");
 
 #[derive(
   Clone, PartialEq, Eq, Debug, Serialize, Deserialize, Encode, Decode, MaxEncodedLen, TypeInfo,
@@ -46,6 +46,6 @@ fn address() {
   use sp_runtime::traits::TrailingZeroInput;
   assert_eq!(
     FEE_ACCOUNT,
-    SeraiAddress::decode(&mut TrailingZeroInput::new(b"FeeAccount")).unwrap()
+    SeraiAddress::decode(&mut TrailingZeroInput::new(b"Coins-fees")).unwrap()
   );
 }