JB/Add foundation submodule, take out old implementations

.gitmodules

@@ -7,3 +7,6 @@
 [submodule "l1-contracts"]
 	path = l1-contracts
 	url = git@github.com:AztecProtocol/aztec3-l1-contracts.git
+[submodule "yarn-project/ethereum.js/foundation"]
+	path = yarn-project/ethereum.js/foundation
+	url = git@github.com:AztecProtocol/foundation.git

yarn-project/ethereum.js/src/contract/abi/abi-coder/ethers/abi-coder.ts

@@ -1,6 +1,6 @@
 import * as errors from './errors.js';
 import { EthAddress } from '../../../../eth_address/index.js';
-import { toBigIntBE, toBufferBE } from '../../../../bigint_buffer/index.js';
+
 import { bufferToHex, hexToBuffer } from '../../../../hex_string/index.js';
 
 const NegativeOne = BigInt(-1);

yarn-project/ethereum.js/src/eth_account/eth_account.ts

@@ -2,7 +2,7 @@ import { EthAddress } from '../eth_address/index.js';
 import { mnemonicToSeedSync } from 'bip39';
 import hdkey from 'hdkey';
 import { default as elliptic } from 'elliptic';
-import { keccak256, randomBytes } from '../crypto/index.js';
+import { keccak256 } from '../crypto/index.js';
 import { decryptFromKeyStoreJson, encryptToKeyStoreJson, KeyStoreJson } from '../keystore/index.js';
 import { EthSignature, hashMessage, recoverFromSignature, signMessage } from '../eth_sign/index.js';
 import { EthTransaction, signedTransaction, signTransaction } from '../eth_transaction/index.js';

yarn-project/ethereum.js/src/eth_address/index.ts

@@ -1,5 +1,4 @@
 import { keccak256String } from '../crypto/index.js';
-import { randomBytes } from '../crypto/random/index.js';
 
 export class EthAddress {
   public static ZERO = new EthAddress(Buffer.alloc(20));

yarn-project/ethereum.js/src/eth_rpc/tx_hash.ts

@@ -1,4 +1,3 @@
-import { randomBytes } from '../crypto/random/index.js';
 
 export class TxHash {
   constructor(private buffer: Buffer) {

yarn-project/ethereum.js/src/keystore/index.ts

@@ -1,7 +1,7 @@
 import aes from 'browserify-aes';
 import { v4 } from 'uuid';
 import { EthAddress } from '../eth_address/index.js';
-import { pbkdf2, scrypt, keccak256, randomBytes } from '../crypto/index.js';
+import { pbkdf2, scrypt, keccak256 } from '../crypto/index.js';
 
 interface ScryptKdfParams {
   dklen: number;