REFACTOR: refactor the exhibition editor view

Refactoring Task

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Problem description

The editor file is too long and contains too much business logic.

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Affected Components/Files:

• src/app/exhibitions/[id]/page.tsx

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Tasks:

• Create separate files for page components.
• Extract as much business logic as possible.
• Move configuration constants(file size, description length, etc) to a separate file. (+ maybe find where the same constants are in other files and change those too)
• Change configuration constant names to UPPER_SNAKE_CASE for better readability.
• Fix any issues regarding linting or good practices.

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Acceptance Criteria:

• The page components are moved to separate files.
• The file contains no image-uploading logic.
• The file contains as little business logic as possible.
• Configuration constants are moved to a separate file.
• The file is under 300 lines.