Add fromSatoshi and toSatoshi to utils function

Add `fromSatoshi` fn that converts an amount from `1e8` to `1e18` token precision. Also here we remove optional `fromPrecision` param in `toSatoshi` fn - we assume we always convert from `1e18` to `1e8` and in `fromSatoshi` we always convert from `1e8` to `1e18`.

sdk/src/lib/utils/index.ts

@@ -1,3 +1,4 @@
 export * from "./hex"
 export * from "./ethereum-signer"
 export * from "./backoff"
+export * from "./satoshi-converter"

sdk/src/lib/utils/satoshi-converter.ts

@@ -0,0 +1,15 @@
+/**
+ * Multiplier to convert satoshi to 1e18 precision.
+ */
+const SATOSHI_MULTIPLIER = 10n ** 10n
+
+export function toSatoshi(amount: bigint) {
+  const remainder = amount % SATOSHI_MULTIPLIER
+  const satoshis = (amount - remainder) / SATOSHI_MULTIPLIER
+
+  return satoshis
+}
+
+export function fromSatoshi(amount: bigint) {
+  return amount * SATOSHI_MULTIPLIER
+}