[Sub-Issue #549.4] Update course documentation for new S11 Data Engineering session

[SkafteNicki]

Parent Issue

Part of #549 - New learning session on data engineering

Phase

Phase 1 - Create New S11 Data Engineering Session

Description

Update all course-level documentation to include the new S11 Data Engineering session. This ensures students and instructors are aware of the new session and can navigate to it properly.

Tasks

• Update main course README to include S11
• Update timeplan.md to add S11 Data Engineering session
  • Add appropriate scheduling information
  • Note that this is a temporary position (will become S4 after refactor)
• Update course overview/index files
• Update any navigation or table of contents files
• Add note that S11 will eventually be renumbered to S4
• Ensure all links to S11 modules work correctly

Files to Update

• Main README.md
• timeplan.md
• Any course overview or navigation files
• Session index/TOC files

Dependencies

• Should be done after Sub-Issue [Refactor] New learning session on data engineering #549.2 and [Refactor] New learning session on data engineering #549.3 (modules created)

Acceptance Criteria

• S11 is properly documented in all course-level files
• Navigation and links work correctly
• Clear note that S11 is temporary and will become S4 after restructuring
• Timeplan updated with appropriate session information
• Documentation is consistent with existing course documentation style