feat: register Unisat as a standard wallet

[bulgakovk]

The PR aims to ensure Wallet Standard compatibility in a non-breaking manner, which will facilitate the migration to the standard of Bitcoin dapps. It wraps the Unisat interface with the Standard Wallet (refer to option B at https://github.com/ExodusMovement/bitcoin-wallet-standard/blob/master/WALLET.md for details). Wallet Standard improves the developer experience for both wallets and dapps by:

1. Resolving the issue of namespace collisions when different wallets compete for the same name;
2. Mitigating race condition problems by ensuring that a dapp can access the window."wallet-name" property even before it's defined by a wallet;
3. For more benefits, refer to the Wallet Standard design doc.

Tested

• I used a wallet standard example dapp and also put <img src={wallet.icon} alt={''}></img> to ensure the icon looks properly. Please make sure you can only see a list of standard wallets there but can't connect because currently Unisat doesn't implement the "pure" Wallet Standard API (refer to option A at https://github.com/ExodusMovement/bitcoin-wallet-standard/blob/master/WALLET.md for details):

[bulgakovk]

This one was converted from https://github.com/unisat-wallet/extension/blob/master/build/_raw/images/logo/logo%40128x.png