Wallet updates (+ breaking changes)

[buffrr]

This PR does the following:

• We no longer use a special descriptor for spaces as that complicates things and could introduce compatibility issues with hardware wallets down the line.
• We use a single pair of descriptors which is now a standard BIP-86
• The wallet export format was updated to use the same format by FullyNoded provided in BDK.
• Simplify the balance structure it now looks like this:

{
  "balance": 923587,
  "details": {
    "immature": 0,
    "trusted_pending": 0,
    "untrusted_pending": 0,
    "confirmed": 931531,
    "dust": 7944
  }
}

Shows a simple available balance that's already calculated along with the details. The "dust" is the combined value of all space outputs we no longer wish to use for their coin value balance = confirmed + trusted_pending - dust

Since now the wallet export format is updated I updated the RPC to expect the full json structure instead of a string I believe this should close #26 as it now takes the json structure as input @Ximik could you verify that this fixes the issue? does that replace PR #27 ?

[Ximik]

I've tested it.

Yes, it fixes the issue and replaces the PR in question.