feat: add contenthash table

[pikonha]

contenthash table

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Description

This pull request adds a new contenthash table to decouple content hash storage from the domains table. This change improves the database structure and allows for more flexible management of content hashes.

Key Changes:

1. Created a new Contenthash entity in packages/gateway/src/entities/index.ts.
2. Updated the PostgresRepository in packages/gateway/src/repositories/postgres.ts to handle the new Contenthash entity:
   • Added setContentHash method to upsert content hash data.
   • Modified getContentHash method to query the new Contenthash table.
   • Updated getSubdomains method to include content hash data.
3. Adjusted the content hash handlers in packages/gateway/src/handlers/contenthash.ts to work with the new table structure.

Related Issue

#161

Changes

• New feature implementation
• Bug fix
• Code refactoring
• Documentation update
• Other (please specify)

Changes to Core Features:

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