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::vector<COutPoint> outputs;
    outputs.reserve(output_params.size());
    for (unsigned int idx = 0; idx < output_params.size(); idx++) {
        const UniValue& o = output_params[idx].get_obj();
        RPCTypeCheckObj(o,
            {
                {"txid", UniValueType(UniValue::VSTR)},
                {"vout", UniValueType(UniValue::VNUM)},
            });
        const uint256 txid(ParseHashO(o, "txid"));
        const int nOutput = find_value(o, "vout").get_int();
        if (nOutput < 0) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, vout must be positive");
        }
        const COutPoint outpt(txid, nOutput);
        const auto it = pwallet->mapWallet.find(outpt.hash);
        if (it == pwallet->mapWallet.end()) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, unknown transaction");
        }
        const CWalletTx& trans = it->second;
        if (outpt.n >= trans.tx->vout.size()) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, vout index out of bounds");
        }
        if (pwallet->IsSpent(outpt.hash, outpt.n)) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, expected unspent output");
        }
        const bool is_locked = pwallet->IsLockedCoin(outpt.hash, outpt.n);
        if (fUnlock && !is_locked) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid parameter, expected locked output");
        }