async downloadVoicePack(options) {
        throw new NotImplementedError();
    }
This method should instruct the vacuum to download a voice pack from `options.url`.
The actual specifications of what exactly is hosted behind options.url depend on the specific vacuum model.
The same goes for the hash, the user should provide a hash or signature as expected by the vacuum.

@abstract
@param {object} options
@param {string} options.url
@param {string} [options.language] lowercase ISO 3166-1 alpha-2 country code
@param {string} [options.hash]
@returns {Promise<void>}