feat(fe): add contest register deregister button

[jihorobert]

Description

• Upgoing, Ongoing Contest의 Register, Deregister버튼 생성

  • Upgoing -> Register, Deregister 둘다 가능
    • Register 혹은 Deregister버튼 누를 시, 신청 완료되었다는 알림창 뜸
    • Register는 Deregister로, Deregister는 Register로 바뀜
  • Ongoing -> Register만 가능
    • Register버튼 누르고나면 버튼 사라짐
• 
• 
• 
• 

close #1541

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines
• Read the Contributing Guidelines and follow the Commit Convention
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Updated (UTC)
codedang	✅ Ready (Inspect)	Visit Preview	Mar 11, 2024 4:49am