feat: add Keypair class and deprecate Account (#17098)

* feat: add Keypair class and deprecate Account

* chore: fix lint issues

* chore: rename TransactionSigner to Signer

web3.js/src/loader.ts

@@ -1,13 +1,13 @@
 import {Buffer} from 'buffer';
 import * as BufferLayout from 'buffer-layout';
 
-import {Account} from './account';
 import {PublicKey} from './publickey';
 import {Transaction, PACKET_DATA_SIZE} from './transaction';
 import {SYSVAR_RENT_PUBKEY} from './sysvar';
 import {sendAndConfirmTransaction} from './util/send-and-confirm-transaction';
 import {sleep} from './util/sleep';
 import type {Connection} from './connection';
+import type {Signer} from './keypair';
 import {SystemProgram} from './system-program';
 
 // Keep program chunks under PACKET_DATA_SIZE, leaving enough room for the
@@ -58,8 +58,8 @@ export class Loader {
    */
   static async load(
     connection: Connection,
-    payer: Account,
-    program: Account,
+    payer: Signer,
+    program: Signer,
     programId: PublicKey,
     data: Buffer | Uint8Array | Array<number>,
   ): Promise<boolean> {