Remove assetDataUtils everywhere (#2373)

* remove assetDataUtils everywhere

* export IAssetDataContract from @0x/contract-wrappers to allow @0x/instant to decode asset data  synchronously

* export generic function `decodeAssetDataOrThrow` and add ERC20Bridge support

* export `hexUtils` from order-utils instead of contracts-test-utils

packages/0x.js/src/index.ts

@@ -1,6 +1,6 @@
 export { getContractAddressesForChainOrThrow, ChainId, ContractAddresses } from '@0x/contract-addresses';
 
-export { assetDataUtils, signatureUtils, generatePseudoRandomSalt } from '@0x/order-utils';
+export { signatureUtils, generatePseudoRandomSalt, decodeAssetDataOrThrow } from '@0x/order-utils';
 
 export {
     ExchangeEventArgs,
@@ -60,14 +60,15 @@ export {
     Order,
     SignedOrder,
     ECSignature,
-    AssetProxyId,
+    AssetData,
     SingleAssetData,
     ERC20AssetData,
+    ERC20BridgeAssetData,
     ERC721AssetData,
     ERC1155AssetData,
     MultiAssetData,
-    MultiAssetDataWithRecursiveDecoding,
     StaticCallAssetData,
+    MultiAssetDataWithRecursiveDecoding,
     SignatureType,
     ZeroExTransaction,
     SignedZeroExTransaction,