Initialize the app media query tokens.
Return the new cache token string or true, if return true, meaning that
it should stop parse tokens.

@param {Object} ctx the parse context
@param {string} buffer the current collect token string
@param {string} separator the current separator that is encountered
@return {boolean|string}
function initAppMediaQueryToken(ctx, buffer, separator) {
    let currToken = buffer.trim();
    let {tokens} = ctx;
    if (currToken) {
        if (initAppMediaTargetInfo(ctx, currToken)) {
            return true;
        }

        tokens.push(buffer);
        tokens.push(separator);

        return '';
    }

    buffer += separator;
    if (buffer.trim()) {
        tokens.push(buffer);
        return '';
    }
    return buffer;
}