function getResBaseURL() {
    const env = process.env.NODE_ENV;
    if (env === "development" && isDevContainer()) {
        return location.protocol + "//" + getDevContainerServerHostname();
    } else if (env === "development" || localStorage.dev === "dev") {
        return location.protocol + "//" + location.hostname + ":3001";
    } else {
        return "";
    }
}
Get the base URL
Mainly used for dev, because the backend and the frontend are in different ports.
@returns {string} Base URL