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

{
    os << num.ToString();
    return os;
}
BasicTestingSetup::BasicTestingSetup(const std::string& chainName)
    : m_path_root{fs::temp_directory_path() / "test_common_" PACKAGE_NAME / g_insecure_rand_ctx_temp_path.rand256().ToString()}
{
    fs::create_directories(m_path_root);
    gArgs.ForceSetArg("-datadir", m_path_root.string());
    ClearDatadirCache();
    SelectParams(chainName);
    SeedInsecureRand();
    gArgs.ForceSetArg("-printtoconsole", "0");
    if (G_TEST_LOG_FUN) LogInstance().PushBackCallback(G_TEST_LOG_FUN);
    InitLogging();
    LogInstance().StartLogging();
    SHA256AutoDetect();
    ECC_Start();
    SetupEnvironment();
    SetupNetworking();
    InitSignatureCache();
    InitScriptExecutionCache();
    fCheckBlockIndex = true;
    static bool noui_connected = false;
    if (!noui_connected) {
        noui_connect();
        noui_connected = true;
    }
}
BasicTestingSetup::~BasicTestingSetup()