Added rewritten class card and drag-and-drop

[sususu5]

Description 🧾

Solved parts of #1165

Added rewritten class card frontend component and drag-and-drop feature.

Testing

Running both the frontend and backend, and comparing the behaviors with the ones of the dev branch

Checklist

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  • feature: for application feature improvement or new features
  • bug: fixing something that previously wasn't working
  • dev: development-side related changes
  • docker: updates to the Docker code
  • setup: changes to the setup/infrastructure of the codebase
  • test: updates to internal testing

[sususu5]

Future improvements:

• Adding the speed effect when shadows appear or disappear
• Handling icon conflicts when shadows overlap
• Handling classcard conflicts when classcards overlap
• Fixing shadow effect issues when draging online classes