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

{
    HTTPReply *reply = static_cast<HTTPReply*>(ctx);
    reply->error = err;
}
#endif
/** Class that handles the conversion from a command-line to a JSON-RPC request,
 * as well as converting back to a JSON object that can be shown as result.
 */
class BaseRequestHandler
{
public:
    virtual ~BaseRequestHandler() {}
    virtual UniValue PrepareRequest(const std::string& method, const std::vector<std::string>& args) = 0;
    virtual UniValue ProcessReply(const UniValue &batch_in) = 0;
};
class GetinfoRequestHandler: public BaseRequestHandler