message: refactor(core): deprecate hdPath, hash256 in baseCoin
  Reduce reliance on bitcoin-specific libraries.
  Issue:
diff: */
  import { BigNumber } from 'bignumber.js';
  import * as bitcoin from '@bitgo/utxo-lib';
  -import { hdPath } from '../bitcoin';
  import * as bip32 from 'bip32';
  import * as Bluebird from 'bluebird';
  import { BitGo } from '../bitgo';
  @@ -23,6 +22,7 @@ import { Enterprises } from './enterprises';
  // re-export account lib transaction types
  import { BaseCoin as AccountLibBasecoin } from '@bitgo/account-lib';
  import { signMessage } from '../bip32util';
  +import * as crypto from 'crypto';
  export type TransactionType = AccountLibBasecoin.TransactionType;
  export interface TransactionRecipient {
  @@ -440,14 +440,17 @@ export abstract class BaseCoin {
  * @returns {{key: string, derivationPath: string}}
  */
  deriveKeyWithSeed({ key, seed }: { key: string; seed: string }): { key: string; derivationPath: string } {
  - const derivationPathInput = bitcoin.crypto.hash256(`${seed}`).toString('hex');
  + function sha256(input) {
  + return crypto.createHash('sha256').update(input).digest();
  + }
  + const derivationPathInput = sha256(sha256(`${seed}`)).toString('hex');
  const derivationPathParts = [
  parseInt(derivationPathInput.slice(0, 7), 16),
  parseInt(derivationPathInput.slice(7, 14), 16),
  ];
  const derivationPath = 'm/999999/' + derivationPathParts.join('/');
  const keyNode = bitcoin.HDNode.fromBase58(key);
  - const derivedKeyNode = hdPath(keyNode).derive(derivationPath);
  + const derivedKeyNode = keyNode.derivePath(derivationPath);
  return {
  key: derivedKeyNode.toBase58(),
  derivationPath: derivationPath,
  