Migrate user preferences from localStorage to manager

[why-arong]

Main idea

This issue aims to transition the storage of user preferences from local storage to the manager's database in the backend.ai project. Specifically, this involves modifying the SettingAtomFamily to ensure that user preferences are stored and retrieved from the database rather than local storage.

• Modify SettingAtomFamily: Update the SettingAtomFamily to fetch and store user preferences from/to the manager's database instead of local storage.
• Focus on User Settings Page: Initially, only the preferences from the user settings page will be stored in the database. Other user preferences will be transitioned to the database in subsequent updates.
• Ensure Data Integrity: Validate preferences using the JSON schema provided by the manager before storing them in the database.

Alternative ideas

Anything else?

This issue is related to the lablup/backend.ai#2349.