Registration page

[dscwebdev]

Figma(Maybe outdated): https://www.figma.com/design/G6jdqDsbhxpvvqlcB3LObt/cxc?node-id=68-125&t=Iq9iBFmSxuPP4dFG-1
Spreadsheet: https://docs.google.com/spreadsheets/d/1TbYa_4GkJdXNnjkb0h3NWMHL2bBARNwjBS_YfLzfj74/edit?gid=0#gid=0

For now, just have the landing page in the /register/cxc.tsx file, input components are still WIP.

Feel free to look at the controller tickets for more documentation on what then endpoints look like

Features:

• Autofill fields
  • You can call {{server_url}}/api/users/user to get the current user and then fill his information based on that
• When users register, hit {{server_url}}/api/admin/events/{{event_id}}/registrants with the body filled with the responses
• When a user has registered, prevent them from registering again
  • You can call {{server_url}}/api/admin/events/{{event_id}}/registrants/{{user_id}} to check for their registration before serving them the page