Plugin/Extension support

[ThienDuc3112]

Is your feature request related to a problem? Please describe.

A clear and concise description of what the problem is. Eg. I'm always frustrated when [...]

Describe the solution you'd like

An interface that user can write code for to change. Eg. Timetable interface that accept color, title, and time slot to display on the timetable, and Planner interface so that you can retrieve and sync course from the timetable and planner

Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.

Additional context

Mostly so that students can easily add / fix / customize their page without the need for dev to add it themselves, or needing to get familiar with the codebase