Done as part of flattening util.
Currently in `util` module we have a bunch of modules that provide
cryptography related functionality.
Create a `crypto` module and move into it the following:
- ecdsa
- schnorr
- key
To improve uniformity and ergonomics, do the following re-names while we
are at it:
- EcdsaSig -> ecdsa::Signature
- SchnorrSig -> schnorr::Signature
- EcdsaSigError -> ecdsa::Error
- SchnorrSigError -> schnorr::Error
- InvalidSchnorrSigSize -> InvalidSignatureSize (this is an error enum variant)
Recently we added a bunch of deprecated re-exports while moving things
out of the util module. Turns out while the code reads like it works,
`deprecated` actually only works for functions, not types or modules
etc.
Remove the non-functional deprecated lines and elect to _not_ re-export
things we moved. Release 0.30 is going to break a lot of code but there
is no real nice way to resolve that. We will need good release notes and
a public apology probably :)
Fix import statements that still rely on `util::bip32` - these should
have been fixed when we moved the `bip32` module.
This example shows how to use the PSBT API for taproot transactions.
We have a simple BIP86-style spend and an example of an inheritance
timelock that can be spent either by the beneficiary via the script
path after a timelock, or via the key path by the benefactor so that
they can refresh the timelock at any time.