Adding delta sync

Synching exchanges take very long, especially if you have lots of transactions.

Assuming the current synch takes all the data every time, I would suggest implementing delta sync. e.g. last 2 days or something similar should be enough since also at night 3 am the data gets synched anyway.

Currently using Binance exchange with a few thousand transactions.

Thanks @radiosuperaktiv for your recommendation! ACCOINTING.com works based on a voting mechanism: the more votes you get, the faster your request moves in the pipeline. The idea behind that is that we prioritize tasks that are more relevant for the entire community, making the development team more efficient. Hope you get some upvotes. Rooting for you!