Add configuration shortcut function

[rodber]

https://xr-docs.chevere.org/configuration/

From this:

new XrInstance(
    new Xr(
        isEnabled: $isEnabled,
        isHttps: $isEnabled,
        host: $host,
        port: $port,
        key: $key
    )
);

To this:

XrConfig(
     isEnabled: $isEnabled,
     isHttps: $isHttps,
     host: $host,
     port: $port,
     key: $key
);