[Chat] keyserver client

[llbartekll]

existing protocol:

protocol Registry {
    func register(account: Account, pubKey: String) async throws
    func resolve(account: Account) async throws -> String
}

rename registry with Keyserver

specs: https://github.com/WalletConnect/walletconnect-specs/blob/main/chat/chat-keyserver.md