docs(be): add jsdoc to admin contest, group, storage / client announcement, workbook modules

[Jaehyeon1020]

Description

Closes TAS-1015

JSDoc을 적용합니다.

적용 모듈 Admin

• Contest
• Group
• Storage

Client

• Announcement (직관적으로 이해 가능한 API가 전부라 docs 추가하지 않았습니다.)
• Workbook (직관적으로 이해 가능한 API가 전부라 docs 추가하지 않았습니다.)

Additional context

isVisible과 관련된 API가 있는데, 따로 문서로 정리 예정입니다.

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

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

[notion-workspace[bot]]

JSDoc 적용: Admin Contest, Group, Storage / Client Announcement, Workbook

[notion-workspace[bot]]

JSDoc 적용: Admin Contest, Group, Storage / Client Announcement, Workbook