[NOTICKET][doc] add guard if filename None

[KM-513][document] add convert to parquet if type file is XLSX and CSV

[NOTICKET][document]: make a clean output to status error unsupported file type

[NOTICKET]: add comments to flag that file type lists must stay in sync

[NOTICKET]: add doctypes endpoint & 10MB file size limit

[NOTICKET]: add CSV and XLSX file type

[NOTICKET]: update folder document_pipelines after pipelines