Persistence and BDK 1.0

In the alpha version of bdk 1.0 we see that they have new options to persistence the wallet data in a file. It's here:

https://docs.rs/bdk_file_store/latest/bdk_file_store/

We need that a lot, the extension is slow in mainnet because every time the wallet is initiated it must sync again...

So we must:

- Watch when the bdk 1.0 is ready for production
- Prepare bitmask-core to be compatible with this
- See if bdk_file_store is compatible with wasm
- If is compatible, implement it, if not we need that so we must see the options and coordinate with bdk team or do our own implementation

I put medium priority because 1.0 is not ready yet but as soon as is about to be ready we need this.