Implements the course schedule feature requested in issue
#[2258](https://github.com/alshedivat/al-folio/issues/2258).
This PR adds a new course schedule feature to the al-folio theme,
allowing academics to easily create and display structured course
information.
**Changes:**
- Added a `courses` collection to organize and display academic courses
- Created course layout and display templates with responsive design
- Implemented organization by year and term with automatic sorting
- Added support for weekly schedule with topics and course materials
- Simplified documentation with a README for course creation
This feature makes it easier for academics to showcase their teaching
materials with a consistent, organized display of course schedules,
helping users create professional teaching pages without custom
implementation.
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Signed-off-by: George Araújo <george.gcac@gmail.com>
Co-authored-by: George Araújo <george.gcac@gmail.com>
