Normalize window config, convert it as quick app display config

@inner
@param {?Object} windowConfig the window config
@return {?Object}
function normalizeWindowConfig(windowConfig) {
    if (!windowConfig) {
        return;
    }

    let result = {};
    // filter the illegal not supported config item
    // and map the weixin config name to quick app
    Object.keys(windowConfig).forEach(k => {
        let newKey = DISPLAY_PAGE_CONFIG_MAP[k];
        if (newKey) {
            result[newKey] = windowConfig[k];
        }
    });
    return result;
}