Add endpoint User Wallet Balance

[abys72]

It would be interesting to add this endpoint to the list, as it allows us to have the entire balance of each category in a single query. That would be in BTC but I find it quite interesting.
This includes spot, earn, futures, bots...

Currently there are several endpoints to collect data for each category, so if you only search for total we will reduce the requests.

Endpoint:
/sapi/v1/asset/wallet/balance

https://developers.binance.com/docs/wallet/asset/query-user-wallet-balance