Fixes an issue with SignOutputRaw in remote signing mode where we
weren't able to sign on the remote signer if we only provided the public
key or only the family/index (and not both).
Fixes part of an issue detected in lightninglabs/loop#457.
This commit was previously split into the following parts to ease
review:
- 2d746f68: replace imports
- 4008f0fd: use ecdsa.Signature
- 849e33d1: remove btcec.S256()
- b8f6ebbd: use v2 library correctly
- fa80bca9: bump go modules
If we're signing for an UTXO that isn't known to the wallet, then the
UTXO's pk script _must_ be set in the sign descriptor. Otherwise we run
into a generic PSBT serialization error when running in a remote signing
setup.
With the remote signing instance now not needing to know anything about
addresses or current derivation indices, we don't need to forward any
such calls to that instance and can simplify the RPCKeyRing
considerably.
In order to support the full range of on-chain functionality, including
importing watch-only accounts in the watch-only instance, we need to
forward some calls like creating new addresses or importing accounts to
the remote signing instance.
