feat: XLSX - CSV (#48) * build(gomod): add tealeg/xlsx as dep * feat(documents): add a csv struct that converts csv to xlsx files * test(document): add test function to test csv-xlsx * feat(xlsx): add a xlsx struct able to convert xlsx files to csv ones * test(documents): add a test function to make sure xlsx - csv works as expected * feat(documents): add changes to integrate the new kind of documents * refactor(csv): remove the outdir * feat(main): add the text kind of document to the main file * docs(readme): add the csv and xlsx kind of documents to the conversion matrix * build(gomod): resolve conflicts on go module