Feat: expose TVLs fetched via lib as part of api endpoints (#1605)

* bump lib to v 2.6.0 and update imports

* return pooled MonetaryAmounts in json format for dex and lending

* align polkadot util-crypto version in dependencies

api/currency-utils.js

@@ -0,0 +1,59 @@
+import {
+    MonetaryAmount,
+    ExchangeRate,
+    Bitcoin,
+    InterBtc,
+    Interlay,
+    KBtc,
+    Kintsugi,
+    Kusama,
+    Polkadot
+} from '@interlay/monetary-js';
+import { isForeignAsset } from "@interlay/interbtc-api";
+import Big from "big.js";
+
+const COINGECKO_ID_BY_CURRENCY_TICKER = {
+    [Bitcoin.ticker]: 'bitcoin',
+    [Kintsugi.ticker]: 'kintsugi',
+    [KBtc.ticker]: 'bitcoin',
+    [Kusama.ticker]: 'kusama',
+    [Polkadot.ticker]: 'polkadot',
+    [Interlay.ticker]: 'interlay',
+    [InterBtc.ticker]: 'bitcoin'
+};
+
+const getCoingeckoId = (currency) => {
+    if (isForeignAsset(currency)) {
+      // Force V[DOT/KSM] prices.
+      switch (currency.ticker) {
+        case 'VDOT':
+          return 'voucher-dot';
+        case 'VKSM':
+          return 'voucher-ksm';
+        default:
+          return currency.foreignAsset.coingeckoId;
+      }
+    }
+    return COINGECKO_ID_BY_CURRENCY_TICKER[currency.ticker];
+};
+
+const getCoingeckoQueryUrl = (vsId, coingeckoIds) => {
+    const idsString = coingeckoIds.join(",");
+    return `https://api.coingecko.com/api/v3/simple/price?vs_currencies=${vsId}&ids=${idsString}`;
+};
+
+const getUsdMonetaryAmount = (monetaryAmount, usdPrice) => {
+    const usdCurrency = {
+        name: "US Dollar",
+        decimals: 2,
+        ticker: "USD",
+        humanDecimals: 2
+    };
+
+    const rate = new Big(usdPrice);
+
+    const xToUsd = new ExchangeRate(monetaryAmount.currency, usdCurrency, rate);
+    return xToUsd.toCounter(monetaryAmount);
+}
+
+export { getCoingeckoId, getCoingeckoQueryUrl, getUsdMonetaryAmount };