libevent seems to have invaded `libbitcoin_common` via `url.cpp`

`url.cpp` is used only from `test/fuzz/string.cpp` and `wallet/rpcwallet.cpp`

libevent should only be required for bitcoind, bitcoin-cli and (due only to the hack of passing wallet names) bitcoin-qt

{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    const CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
            RPCHelpMan{"signmessage",
                "\nSign a message with the private key of an address" +
        HELP_REQUIRING_PASSPHRASE,
                {
                    {"address", RPCArg::Type::STR, RPCArg::Optional::NO, "The bitcoin address to use for the private key."},
                    {"message", RPCArg::Type::STR, RPCArg::Optional::NO, "The message to create a signature of."},
                },
                RPCResult{
                    RPCResult::Type::STR, "signature", "The signature of the message encoded in base 64"
                },
                RPCExamples{
            "\nUnlock the wallet for 30 seconds\n"
            + HelpExampleCli("walletpassphrase", "\"mypassphrase\" 30") +
            "\nCreate the signature\n"