Fix LibreOffice support for Office document processing

[rex993]

• Install libreoffice-nogui in Docker container
• Add soffice availability check on initialization
• Implement unified Office-to-PDF conversion method
• Add support for DOCX, PPTX, and XLSX files
• Include additional unstructured extras for Office formats
• Add unstructured support for Office documents when ColPali is disabled

[jazzberry-ai]

Bug Report

Name	Severity	Example test case	Description
Overly aggressive text sanitization	Medium	Upload a document with specific Unicode characters.	The _sanitize_text function in core/parser/morphik_parser.py might remove valid Unicode characters, leading to data loss.
Unhandled soffice failure	Medium	Attempt to convert an Office document to PDF when the output directory is not writable.	The _convert_office_to_pdf function in core/services/document_service.py doesn't handle the case where the soffice command fails to create the PDF file in the expected location, potentially leading to uninformative error messages.
Missing empty input file check	Low	Upload an empty Office document.	The _convert_office_to_pdf function in core/services/document_service.py doesn't check if the input file is empty before calling soffice, potentially leading to unnecessary processing and empty PDF files.
Missing runtime soffice availability check	Low	Start the service and then uninstall LibreOffice.	The _convert_office_to_pdf function in core/services/document_service.py only checks for soffice availability on initialization, and does not account for it becoming unavailable at a later time.

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[jazzberry-ai]

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