Feature: Add Privacy Cash protocol

[daniel0ar]

Overview

Since this project was originally going to mimic the work of Kohaku on Ethereum but here on Solana, I wanted to have the user chose which protocol they want to use to make their balances private (Shadowwire and Privacy Cash), but this turned out incompatible with browser extensions and I lacked support. Here's the pending issue:

Problem

ERROR in ./node_modules/.pnpm/@lightprotocol+hasher.rs@0.2.1/node_modules/@lightprotocol/hasher.rs/dist/browser-fat/es/index_browser_fat.js
  × Module not found: Can't resolve 'light_wasm_hasher_bg.wasm' in '/home/daniel/Documents/Hackathons/SolanaPrivacyHack/ruma-extension/node_modules/.pnpm/@lightprotocol+hasher.rs@0.2.1/node_modules/@lightprotocol/hasher.rs/dist/browser-fat/es'
     ╭─[256:25]
 254 │ 
 255 │     if (typeof module_or_path === 'undefined') {
 256 │         module_or_path = new URL('light_wasm_hasher_bg.wasm', import.meta.url);
     ·                          ─────────────────────────────────────────────────────
 257 │     }
 258 │     const imports = __wbg_get_imports$1();
     ╰────


ERROR in ./node_modules/.pnpm/@lightprotocol+hasher.rs@0.2.1/node_modules/@lightprotocol/hasher.rs/dist/browser-fat/es/index_browser_fat.js
  × Module not found: Can't resolve 'hasher_wasm_simd_bg.wasm' in '/home/daniel/Documents/Hackathons/SolanaPrivacyHack/ruma-extension/node_modules/.pnpm/@lightprotocol+hasher.rs@0.2.1/node_modules/@lightprotocol/hasher.rs/dist/browser-fat/es'
     ╭─[522:25]
 520 │ 
 521 │     if (typeof module_or_path === 'undefined') {
 522 │         module_or_path = new URL('hasher_wasm_simd_bg.wasm', import.meta.url);
     ·                          ────────────────────────────────────────────────────
 523 │     }
 524 │     const imports = __wbg_get_imports();
     ╰────


ERROR in ./node_modules/.pnpm/privacycash@1.1.11_bufferutil@4.1.0_fastestsmallesttextencoderdecoder@1.0.22_typescript@5.0.2_utf-8-validate@5.0.10/node_modules/privacycash/dist/utils/encryption.js 2:1-33
  × Module not found: Can't resolve 'crypto' in '/home/daniel/Documents/Hackathons/SolanaPrivacyHack/ruma-extension/node_modules/.pnpm/privacycash@1.1.11_bufferutil@4.1.0_fastestsmallesttextencoderdecoder@1.0.22_typescript@5.0.2_utf-8-validate@5.0.10/node_modules/privacycash/dist/utils'
   ╭─[2:0]
 1 │ import nacl from 'tweetnacl';
 2 │ import * as crypto from 'crypto';
   · ─────────────────────────────────
 3 │ import { Utxo } from '../models/utxo.js';
 4 │ import { WasmFactory } from '@lightprotocol/hasher.rs';