WalletConnect: Support versioned signature schemes

[cthulhu-rider]

Context

NeoFS supports WalletConnect signature scheme implemented here. It was added almost 2y ago and follows algo from neon-js lib of those days

since then neon-js library has moved forward, and, starting from this, now it supports multiple signature versions

Proposal

version the signature scheme similarly to neon-js: add the version to the signature and use it during verification. Missing token will still be treated as legacy schema

[roman-khimov]

signMessageNew() looks interesting, signing arbitrary data without any prefixes/suffixes.

[roman-khimov]

It still adds some salt though. And there is also signMessageWithoutSalt provided by DAPI that doesn't do that, but it adds prefix (010001f0).