fix: remove all firebase hosting related files

[thisisWooyeol]

PR Title: Github actions를 통한 firebase hosting 기능 제거

Related Issue(s):

PR #3 에서 deploy & hosting workflow에 오류 발생

PR Description:

• 빌드 및 deploy관련 문제는 해결을 했으나 firebase hosting은 only static assets의 hosting만 지원한다는 것을 뒤늦게 발견해
  firebase hosting관련 workflow파일을 전부 삭제
• public 폴더의 경우 hosting 대상이 되는 정적 assets이 담긴 폴더로 마찬가지로 firebase hosting과 관련된 데이터이므로 삭제

Changes Included:

• Added new feature(s)
• Fixed identified bug(s)
• Updated relevant documentation

Notes for Reviewer:

• 추후 google app engine을 이용한 deploy로 workflow를 수정해 반영할 예정

Reviewer Checklist:

• Code is written in clean, maintainable, and idiomatic form.
• Automated test coverage is adequate.
• All existing tests pass.
• Manual testing has been performed to ensure the PR works as expected.
• Code review comments have been addressed or clarified.

Additional Comments: