[META] Roadmap for v3.1

Next steps for v3.1.1:

• Proceed to security tests
• Improve file storage client tests (index generation, etc.)
• Improve xnttsql tests
• Completed online documentation
• Be more transparent to specify where AI was used
• Include a SPARQL storage client as an example for Query Language client base with no dependencies
• Make sure xnttsql works with SQL Server (#3623530 and #3599491)