Migrate all btcd dependencies to the new per-package v2 modules (wire/v2,
txscript/v2, chaincfg/v2, chainhash/v2, btcutil/v2, psbt/v2, btcec/v2)
introduced by btcd v0.26.0, and pin the tagged ecosystem versions:
btcwallet v0.17.0, neutrino v0.18.0 and lightning-onion v1.4.0.
The bulk of the import rewrite was produced by the scripted diff from
https://github.com/btcsuite/btcd/pull/2547 (followed by 'make rpc'). The
address symbols that moved out of btcutil into the new address package
are imported as btcaddr where a local "address" variable would otherwise
shadow them. The go.mod/go.sum updates and the remaining manual
compilation fixes are folded into this single commit so it builds on its
own (the migration was previously split into a reproducible scripted-diff
plus follow-ups, intended to be squashed on merge).
We have the same helpers for writing and reading a wire.Outpoint type
defined separately in a couple places. We will want to use these from
the graph db package soon though so instead of defining them again
there, this commit unifies things and creates a single exported set of
helpers. The next commit will make use of these.
In preparation for moving the graph related schema structs to the graph
package in an upcoming commit, we move these methods to the graph
package. The structs we will move make use of these methods but we still
import them from channeldb so as to keep the ReadElement and
WriteElement helpers working as they do today.
