Add extra features for testcard

[wowwood]

    const useUTC = params.has('utc') ? params.get('utc') === 'true' || params.get('utc') === 'on' : false;
    const useMillis = params.has('millis') ? params.get('millis') === 'true' || params.get('millis') === 'on' : false;
    const stationName = params.has('station') ? params.get('station') : '';
    const programName = params.has('program') ? params.get('program') : '';
    const stationLogo = params.has('logo') ? params.get('logo') : null;
    const customSong = params.has('song') ? params.get('song') : null;
    const customVolume = params.has('volume') ? params.get('volume') : null;
    const ttsIdentText = params.has('ttsIdentText') ? params.get('ttsIdentText') : null;
    const ttsIdentLang = params.has('ttsIdentLang') ? params.get('ttsIdentLang') : 'en';
    const ttsIdentVoice = params.has('ttsIdentVoice') ? params.get('ttsIdentVoice') : null;
    const identDelay = params.has('identDelay') ? parseInt(params.get('identDelay')) : 5000;
    const identSeperate = params.has('identSeperate') ? params.get('identSeperate') === 'true' || params.get('identSeperate') === 'on' : false;
    const identVolume = params.has('identVolume') ? parseInt(params.get('ttsVolume')) : 100;
    const identFile = params.has('identFile') ? params.get('identFile') : null;

@craftbyte has added some more features to their test card generator. This needs adding to the test card page

you can do either ttsIdentText or identFile