python sdk tutorial: work with wallet.json files instead of private key files

[matthiaszimmermann]

golembase python sdk readme [1] suggests to work with private.key files that store private keys in plain text. this issue proposes to work with wallet json files instead [1]

proposal for wallet.py

import getpass
import json
import sys
from pathlib import Path

from eth_account import Account

WALLET_PATH = Path("wallet.json")

if WALLET_PATH.exists():
    print(f'File "{WALLET_PATH}" already exists. Aborting.')
    sys.exit(0)

password = getpass.getpass("Enter wallet password: ")
account = Account.create()
encrypted = account.encrypt(password)

with WALLET_PATH.open("w") as f:
    json.dump(encrypted, f)

print(f"Account address: {account.address}")
print(f"Wallet file: {WALLET_PATH}")

and reconstructing the privat key from the wallet file

with WALLET_PATH.open("r") as f:
    wallet_json = json.load(f)
    private_key = Account.decrypt(wallet_json, password)