Removes Snowbridge parachain directory (#3186)

Removes the `bridges/snowbridge/parachain` directory and moves
everything up to under `snowbridge` directly. We are cleaning up our
local dev env after merging our crates into the polkadot-sdk.

---------

Co-authored-by: claravanstaden <Cats 4 life!>

bridges/snowbridge/primitives/core/src/pricing.rs

@@ -0,0 +1,67 @@
+use codec::{Decode, Encode, MaxEncodedLen};
+use scale_info::TypeInfo;
+use sp_arithmetic::traits::{BaseArithmetic, Unsigned, Zero};
+use sp_core::U256;
+use sp_runtime::{FixedU128, RuntimeDebug};
+use sp_std::prelude::*;
+
+#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, MaxEncodedLen, TypeInfo)]
+pub struct PricingParameters<Balance> {
+	/// ETH/DOT exchange rate
+	pub exchange_rate: FixedU128,
+	/// Relayer rewards
+	pub rewards: Rewards<Balance>,
+	/// Ether (wei) fee per gas unit
+	pub fee_per_gas: U256,
+}
+
+#[derive(Clone, Encode, Decode, PartialEq, RuntimeDebug, MaxEncodedLen, TypeInfo)]
+pub struct Rewards<Balance> {
+	/// Local reward in DOT
+	pub local: Balance,
+	/// Remote reward in ETH (wei)
+	pub remote: U256,
+}
+
+#[derive(RuntimeDebug)]
+pub struct InvalidPricingParameters;
+
+impl<Balance> PricingParameters<Balance>
+where
+	Balance: BaseArithmetic + Unsigned + Copy,
+{
+	pub fn validate(&self) -> Result<(), InvalidPricingParameters> {
+		if self.exchange_rate == FixedU128::zero() {
+			return Err(InvalidPricingParameters)
+		}
+		if self.fee_per_gas == U256::zero() {
+			return Err(InvalidPricingParameters)
+		}
+		if self.rewards.local.is_zero() {
+			return Err(InvalidPricingParameters)
+		}
+		if self.rewards.remote.is_zero() {
+			return Err(InvalidPricingParameters)
+		}
+		Ok(())
+	}
+}
+
+/// Holder for fixed point number implemented in <https://github.com/PaulRBerg/prb-math>
+#[derive(Clone, Encode, Decode, RuntimeDebug, TypeInfo)]
+#[cfg_attr(feature = "std", derive(PartialEq))]
+pub struct UD60x18(U256);
+
+impl From<FixedU128> for UD60x18 {
+	fn from(value: FixedU128) -> Self {
+		// Both FixedU128 and UD60x18 have 18 decimal places
+		let inner: u128 = value.into_inner();
+		UD60x18(inner.into())
+	}
+}
+
+impl UD60x18 {
+	pub fn into_inner(self) -> U256 {
+		self.0
+	}
+}