Save wallet data to file

save essential wallet data to file
selene-specific metadata remains in global sql db
use walletHash as filename
use walletHash as sql primary key
each wallet can manage its own sql db file for addresses, history, and utxos

https://codeberg.org/Flowee/pay/wiki/dev/CHIP-wallet-backup

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information