static async fromContent(qnaContent) {
        let parsedContent = await parseFileContents(qnaContent, false)
        return new QnAMaker(new KB(parsedContent.qnaJsonStructure), new Alterations(parsedContent.qnaAlterations))
    }
Builds a QnAMaker instance from a qna content.
@param {Qna} qnaContent QnA content
@returns {QnAMaker} new QnAMaker instance
@throws {exception} Throws on errors. exception object includes errCode and text.